16Hit1600
Geometry and TrigonometryEasy–MediumEqual sides of an isosceles triangle from its perimeter

Geometry and Trigonometry practice question

An isosceles triangle has a perimeter of 32 centimetres and a base of 12 centimetres. What is the length, in centimetres, of each of the two equal sides?

Answer: 10

The two equal sides together make 32 − 12 = 20 centimetres, so each is 10.

Common wrong answers

If you answered 12
12 is the base, not an equal side.
If you answered 20
20 is the total of the two equal sides; each is half of that.
If you answered 6.67
6.67 is 20/3, dividing among three sides instead of two.

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