Question

An isosceles triangle is one in which two of the sides are congruent. The perimeter of an isosceles triangle is 21 mm. If the length of the congruent sides is 3 times the length of the third side, find the dimensions of the triangle.

Answer 1

base = 3 mm and congruent sides = 9 mm

Explanation:

let the length of the third side be x then the length of the congruent sides are 3x

the perimeter is the sum of the 3 sides

given perimeter = 21 , then

3x + 3x + x = 21

7x = 21 ( divide both sides by 7 )

x = 3

then third side is 3 mm and congruent sides = 3 × 3 = 9 mm