Explore related knowledge and questions →

Question 34464: Exact Proportion Check

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

Return to catalogue page 173

← Question derivation index · Original question batch

R0067-34464 · q-20260930-r02-proportion-verification-0014

Original question and givens

In the rational numerical-ratio setting, is 1:(6)=-4:(-30) a valid proportion? Both consequents are nonzero.

  • G001 — In the rational numerical-ratio setting, is 1:(6)=-4:(-30) a valid proportion? Both consequents are nonzero.

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

source roles = [qf-proportion-verification, [a, b, c, d, operation]]

After

derived = [proportion_verification, no-invented-domain]

Conditions: none

Check THIS bank’s keys/operation/domain:legacy table underscores,MOD50 local hyphens;permissive BASE data acquires no unknown-field restriction.Keep Number.isInteger and SAFE source guards distinct,while preserving ORIGINAL JSON number representations.

Step identifiers and dependencies

Rule: R67_SOURCE_specific_keys_operation_domain_and_numeric_bank · Uses: G001

S002 · calculation

Before

Proportion ORIGINAL a times d := mul(1, -30)

After

Proportion ORIGINAL a times d = -30

Conditions: none

Calculate exactly from ORIGINAL ordered operands.Legacy derived integers are not recapped at the RAW SAFE bound;MOD50 rationals separately retain the NAIVE pre-reduction source envelope.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S001

S003 · calculation

Before

Proportion ORIGINAL c times b := mul(-4, 6)

After

Proportion ORIGINAL c times b = -24

Conditions: none

Calculate exactly from ORIGINAL ordered operands.Legacy derived integers are not recapped at the RAW SAFE bound;MOD50 rationals separately retain the NAIVE pre-reduction source envelope.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S002

S004 · implies

Before

source roles = [1, 6, -4, -30]

After

derived = [-30, -24, No]

Conditions: none

FIRST require nonzero b,d.Then a/b=c/d IFF ad=cb.Negative denominators are allowed;equation equivalence survives multiplication by a nonzero number.Never certify undefined ratios using0=0 with zero denominators.

Step identifiers and dependencies

Rule: Proportion_NONzero_denominators_crossmultiply_EQUIVALENCE · Uses: G001, S003

Reverse checks

  • S004 · premise_and_result_audit — Reverse-audit THIS step against the ORIGINAL roles,complete premises and field order.Distinguish implication from equivalence;preserve originals,English,MKOs,ASTs and review states.Finite checks are not independent review or general formal proof.
  • S003 · premise_and_result_audit — Recompute Proportion ORIGINAL c times b with exact rational arithmetic, not rounded decimals.
  • S002 · premise_and_result_audit — Recompute Proportion ORIGINAL a times d with exact rational arithmetic, not rounded decimals.
  • S001 · premise_and_result_audit — Reverse-audit THIS step against the ORIGINAL roles,complete premises and field order.Distinguish implication from equivalence;preserve originals,English,MKOs,ASTs and review states.Finite checks are not independent review or general formal proof.

Result

No

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: e69cb5f1cc7673b528d60127df0d0c21449e8998d8eaa47e2cda716a4ddd1460
  • candidate record SHA-256: 8d5b806066dc0c274f9629ddab9472886923054a177cb263baf1d865a872b65c
  • semantic review receipt SHA-256: c89efa383b67bb2cf25bcf16160b9f5f614bbe5e5e791f4d7f58234d17a3371c
  • question-first witness SHA-256: 12766d451c5375842b4fc2843ae94807ec55f15763a916558026912a13873d57
  • Lean: NOT_RUN · human review: NOT_PERFORMED
Same-source full JSON