Question

Two equal sides of an isosceles triangle are 5y – 2 and 4y + 9 units. The third side is 2y + 5 units. Find y and the perimeter of the triangle.

Answer 1

Given that 5y – 2 & 4y + 9 are the equal sides of an isosceles triangle.

The 2 sides are equal

∴ 5y – 4y = 9 + 2 (by transposing)

∴ y = 11

∴ 1st side = 5y – 2 = 5 x 11-2 = 55 – 2 = 53

2nd side = 53

3rd side = 2y + 5 = 2 x 11 + 5 = 22 + 5 = 27

Perimeter is the sum of all 3 sides

∴ P = 53 + 53 + 27 = 133 units