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Question 6572: Opposite Midpoint and Three Squared Segments

On this page
  1. Original question and givens
  2. Definition and scope
  3. Step-by-step derivation
  4. Reverse checks
  5. Result
  6. This question review and source binding

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R0012-06572 · q-20261009-advance-20261013-r07-triangle-0097

Original question and givens

In one equal-unit orthogonal Euclidean frame, labeled A,B,C have indices 1,2,3 and points=[[0, 22], [-21, 0], [22, 0]]. The points are distinct and noncollinear, vertex=1, and M is the opposite side’s midpoint. Give (Mx, My, first opposite endpoint-to-M square, second endpoint-to-M square, vertex-to-M square). Use exact reduced fractions with positive denominators, retaining /1 for integers.

  • G001 — In one equal-unit orthogonal Euclidean frame, labeled A,B,C have indices 1,2,3 and points=[[0, 22], [-21, 0], [22, 0]]. The points are distinct and noncollinear, vertex=1, and M is the opposite side’s midpoint. Give (Mx, My, first opposite endpoint-to-M square, second endpoint-to-M square, vertex-to-M square). Use exact reduced fractions with positive denominators, retaining /1 for integers.

Definition and scope

Use the original question domain, assumptions and cited MKO definitions. This item has second-context mathematical and bilingual review, with the model, answer and every arithmetic step independently recomputed from the original parameters; the source question remains a candidate.

Step-by-step derivation

S001 · implies

Before

[[0, 22], [-21, 0], [22, 0]]

After

original vertex labels1,2,3 in an equal-unit orthogonal Euclidean frame

Conditions: none

Retain the original A,B,C order;the squared-coordinate formula uses equal units and orthogonal axes.Do not read values from a sketch or assume candidate vertices already form a triangle.

Step identifiers and dependencies

Rule: labelled_triangle_coordinate_scope · Uses: G001

S002 · implies

Before

[[0, 22], [-21, 0], [22, 0]]

After

three distinct points=Yes

Conditions: none

Check distinctness separately from noncollinearity;collinear points may be distinct,while repeated vertices do not form a proper triangle.

Step identifiers and dependencies

Rule: distinct_triangle_vertex_check · Uses: G001, S001

S003 · calculation

Before

ABC first vector component0 := sub(-21, 0)

After

ABC first vector component0 = -21

Conditions: none

The first edge vector is the second vertex minus the first.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S002

S004 · calculation

Before

ABC first vector component1 := sub(0, 22)

After

ABC first vector component1 = -22

Conditions: none

The first edge vector is the second vertex minus the first.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S003

S005 · calculation

Before

ABC second vector component0 := sub(22, 0)

After

ABC second vector component0 = 22

Conditions: none

The second edge vector is the third vertex minus that same first vertex.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S004

S006 · calculation

Before

ABC second vector component1 := sub(0, 22)

After

ABC second vector component1 = -22

Conditions: none

The second edge vector is the third vertex minus that same first vertex.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S005

S007 · calculation

Before

ABC cross positive term := mul(-21, -22)

After

ABC cross positive term = 462

Conditions: none

Compute u_x v_y first.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S006

S008 · calculation

Before

ABC cross negative term := mul(-22, 22)

After

ABC cross negative term = -484

Conditions: none

Compute u_y v_x separately,retaining subtraction for the next step.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S007

S009 · calculation

Before

ABC signed determinant := sub(462, -484)

After

ABC signed determinant = 946

Conditions: none

Subtract to obtain signed double area;do not erase label orientation with an absolute value.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S008

S010 · implies

Before

distinct=Yes;signed determinant=946

After

proper triangle=Yes

Conditions: none

A proper triangle needs distinct vertices and nonzero determinant;this judges the supplied coordinates,not a general geometric construction proof.

Step identifiers and dependencies

Rule: triangle_nondegenerate_coordinate_qualification · Uses: G001, S009

S011 · implies

Before

marked vertex=1

After

opposite endpoints=[2, 3]

Conditions: none

The opposite-side endpoints are the other two original labels,not a reordered coordinate or side-length list.

Step identifiers and dependencies

Rule: original_label_opposite_side · Uses: G001, S010

S012 · calculation

Before

midpoint coordinate sum0 := sum(-21, 22)

After

midpoint coordinate sum0 = 1

Conditions: none

Add matching coordinates of the opposite endpoints.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S011

S013 · calculation

Before

midpoint coordinate0 := div(1, 2)

After

midpoint coordinate0 = 1/2

Conditions: none

Divide the full sum by2,retaining the reduced rational value.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S012

S014 · calculation

Before

midpoint coordinate sum1 := sum(0, 0)

After

midpoint coordinate sum1 = 0

Conditions: none

Add matching coordinates of the opposite endpoints.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S013

S015 · calculation

Before

midpoint coordinate1 := div(0, 2)

After

midpoint coordinate1 = 0

Conditions: none

Divide the full sum by2,retaining the reduced rational value.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S014

S016 · calculation

Before

first endpoint to midpoint coordinate difference0 := sub(-21, 1/2)

After

first endpoint to midpoint coordinate difference0 = -43/2

Conditions: none

Subtract matching coordinates,allowing rational midpoint coordinates.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S015

S017 · calculation

Before

first endpoint to midpoint difference squared0 := square(-43/2)

After

first endpoint to midpoint difference squared0 = 1849/4

Conditions: none

Square each difference;its sign does not affect squared length.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S016

S018 · calculation

Before

first endpoint to midpoint coordinate difference1 := sub(0, 0)

After

first endpoint to midpoint coordinate difference1 = 0

Conditions: none

Subtract matching coordinates,allowing rational midpoint coordinates.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S017

S019 · calculation

Before

first endpoint to midpoint difference squared1 := square(0)

After

first endpoint to midpoint difference squared1 = 0

Conditions: none

Square each difference;its sign does not affect squared length.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S018

S020 · calculation

Before

first endpoint to midpoint squared distance := sum(1849/4, 0)

After

first endpoint to midpoint squared distance = 1849/4

Conditions: none

Add the two squares in the equal-unit orthogonal L2 frame.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S019

S021 · calculation

Before

second endpoint to midpoint coordinate difference0 := sub(22, 1/2)

After

second endpoint to midpoint coordinate difference0 = 43/2

Conditions: none

Subtract matching coordinates,allowing rational midpoint coordinates.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S020

S022 · calculation

Before

second endpoint to midpoint difference squared0 := square(43/2)

After

second endpoint to midpoint difference squared0 = 1849/4

Conditions: none

Square each difference;its sign does not affect squared length.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S021

S023 · calculation

Before

second endpoint to midpoint coordinate difference1 := sub(0, 0)

After

second endpoint to midpoint coordinate difference1 = 0

Conditions: none

Subtract matching coordinates,allowing rational midpoint coordinates.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S022

S024 · calculation

Before

second endpoint to midpoint difference squared1 := square(0)

After

second endpoint to midpoint difference squared1 = 0

Conditions: none

Square each difference;its sign does not affect squared length.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S023

S025 · calculation

Before

second endpoint to midpoint squared distance := sum(1849/4, 0)

After

second endpoint to midpoint squared distance = 1849/4

Conditions: none

Add the two squares in the equal-unit orthogonal L2 frame.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S024

S026 · calculation

Before

marked vertex to midpoint coordinate difference0 := sub(0, 1/2)

After

marked vertex to midpoint coordinate difference0 = -1/2

Conditions: none

Subtract matching coordinates,allowing rational midpoint coordinates.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S025

S027 · calculation

Before

marked vertex to midpoint difference squared0 := square(-1/2)

After

marked vertex to midpoint difference squared0 = 1/4

Conditions: none

Square each difference;its sign does not affect squared length.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S026

S028 · calculation

Before

marked vertex to midpoint coordinate difference1 := sub(22, 0)

After

marked vertex to midpoint coordinate difference1 = 22

Conditions: none

Subtract matching coordinates,allowing rational midpoint coordinates.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S027

S029 · calculation

Before

marked vertex to midpoint difference squared1 := square(22)

After

marked vertex to midpoint difference squared1 = 484

Conditions: none

Square each difference;its sign does not affect squared length.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S028

S030 · calculation

Before

marked vertex to midpoint squared distance := sum(1/4, 484)

After

marked vertex to midpoint squared distance = 1937/4

Conditions: none

Add the two squares in the equal-unit orthogonal L2 frame.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S029

S031 · implies

Before

endpoint squares=(1849/4,1849/4);vertex-to-midpoint square=1937/4

After

endpoint equality does not make every median half the opposite side

Conditions: none

The midpoint is equally distant from the endpoints,at half the side length.But a general third-vertex median need not have that length;do not apply a right-hypotenuse special case to arbitrary labels.

Step identifiers and dependencies

Rule: midpoint_endpoint_vs_median_distinction · Uses: G001, S030

Reverse checks

  • S031 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S030 · premise_and_result_audit — Recompute marked vertex to midpoint squared distance with exact rational arithmetic, not rounded decimals.
  • S029 · premise_and_result_audit — Recompute marked vertex to midpoint difference squared1 with exact rational arithmetic, not rounded decimals.
  • S028 · premise_and_result_audit — Recompute marked vertex to midpoint coordinate difference1 with exact rational arithmetic, not rounded decimals.
  • S027 · premise_and_result_audit — Recompute marked vertex to midpoint difference squared0 with exact rational arithmetic, not rounded decimals.
  • S026 · premise_and_result_audit — Recompute marked vertex to midpoint coordinate difference0 with exact rational arithmetic, not rounded decimals.
  • S025 · premise_and_result_audit — Recompute second endpoint to midpoint squared distance with exact rational arithmetic, not rounded decimals.
  • S024 · premise_and_result_audit — Recompute second endpoint to midpoint difference squared1 with exact rational arithmetic, not rounded decimals.
  • S023 · premise_and_result_audit — Recompute second endpoint to midpoint coordinate difference1 with exact rational arithmetic, not rounded decimals.
  • S022 · premise_and_result_audit — Recompute second endpoint to midpoint difference squared0 with exact rational arithmetic, not rounded decimals.
  • S021 · premise_and_result_audit — Recompute second endpoint to midpoint coordinate difference0 with exact rational arithmetic, not rounded decimals.
  • S020 · premise_and_result_audit — Recompute first endpoint to midpoint squared distance with exact rational arithmetic, not rounded decimals.
  • S019 · premise_and_result_audit — Recompute first endpoint to midpoint difference squared1 with exact rational arithmetic, not rounded decimals.
  • S018 · premise_and_result_audit — Recompute first endpoint to midpoint coordinate difference1 with exact rational arithmetic, not rounded decimals.
  • S017 · premise_and_result_audit — Recompute first endpoint to midpoint difference squared0 with exact rational arithmetic, not rounded decimals.
  • S016 · premise_and_result_audit — Recompute first endpoint to midpoint coordinate difference0 with exact rational arithmetic, not rounded decimals.
  • S015 · premise_and_result_audit — Recompute midpoint coordinate1 with exact rational arithmetic, not rounded decimals.
  • S014 · premise_and_result_audit — Recompute midpoint coordinate sum1 with exact rational arithmetic, not rounded decimals.
  • S013 · premise_and_result_audit — Recompute midpoint coordinate0 with exact rational arithmetic, not rounded decimals.
  • S012 · premise_and_result_audit — Recompute midpoint coordinate sum0 with exact rational arithmetic, not rounded decimals.
  • S011 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S010 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S009 · premise_and_result_audit — Recompute ABC signed determinant with exact rational arithmetic, not rounded decimals.
  • S008 · premise_and_result_audit — Recompute ABC cross negative term with exact rational arithmetic, not rounded decimals.
  • S007 · premise_and_result_audit — Recompute ABC cross positive term with exact rational arithmetic, not rounded decimals.
  • S006 · premise_and_result_audit — Recompute ABC second vector component1 with exact rational arithmetic, not rounded decimals.
  • S005 · premise_and_result_audit — Recompute ABC second vector component0 with exact rational arithmetic, not rounded decimals.
  • S004 · premise_and_result_audit — Recompute ABC first vector component1 with exact rational arithmetic, not rounded decimals.
  • S003 · premise_and_result_audit — Recompute ABC first vector component0 with exact rational arithmetic, not rounded decimals.
  • S002 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S001 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.

Result

(1/2, 0/1, 1849/4, 1849/4, 1937/4)

The full substitutions and premise checks give the original answer; source identity,format and status are unchanged.

This question review and source binding

Review date: 2026-10-26

Original questions, answers, step expressions, numeric ASTs and historical records are retained. Source candidate labels remain historical and are not overwritten as formal proof.

Source hashes and review receipts
  • input commit: 0f7be61e2c22317a4075561dc822c87d881a50db
  • original question SHA-256: b7dbe8e299e442f45e8c63cdac644f07403069c0351e326ba4a304d58cfdcfa8
  • candidate record SHA-256: c161b557c9d9e6cb64b7a1c2558f457231b9d79e5b5262a502b31871269bfccc
  • semantic review receipt SHA-256: 90dbc494b2d34ef51f412dcff63cfcc1a2215d038bff71f38f5dded4c64faf00
  • question-first witness SHA-256: b72a3b8bcf10f584396e0dd5198c657b0934a71864e5a3fa6321d7a613aef9f9
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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