alleryA rectangle with sides 5 and 7 disproves 'all rectangles are squares'. It is a:
AConjecture
BCounterexample
CPostulate
DDefinition
Answer & Solution
Correct answer: B. Counterexample
1. The claim says every rectangle is a square.
2. One rectangle that is not a square contradicts it, so it is a counterexample.
3. It does not assume or prove anything, so the other terms fail.
_Source: Wikipedia, "Counterexample" (rev ?), section "In mathematics"_
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