In a geometry lesson, a student says 'That one isn't equilateral. This side is shorter.' Which restatement demonstrates correct use of isn't to negate the statement?

In a geometry lesson, a student says 'That one isn't equilateral. This side is shorter.' Which restatement demonstrates correct use of isn't to negate the statement?

• A. That isn't an equilateral triangle because one side is shorter.
• B. This triangle is equilateral because all sides are equal.
• C. The triangle is not equilateral because one side is shorter.
• D. The sides form a triangle, not equilateral.

Answer: (A)

Negation with isn't means denying the same property about the same subject, using the contraction isn't to reverse the claim. That isn't an equilateral triangle because one side is shorter. This version keeps the same subject and the negated property, and adds a justification for why it isn’t equilateral. Other restatements either affirm the positive or use not instead of isn't, which doesn’t show the contracted form being tested.

Negation with isn't means denying the same property about the same subject, using the contraction isn't to reverse the claim.

That isn't an equilateral triangle because one side is shorter. This version keeps the same subject and the negated property, and adds a justification for why it isn’t equilateral. Other restatements either affirm the positive or use not instead of isn't, which doesn’t show the contracted form being tested.