Question

The two equal sides of an isosceles triangle are given as (x+2)cm and the third is (x+6)cm. If the perimeter of the triangle is 385cm, find the value of x.

Answer 1

The two equal sides of isoscles triangle = x+2 cm
Since there are two sides, x+2 repeats twice

The third unequal side = x+6 cm

Perimeter of triangle = 385 cm

Sum of all three sides = perimeter of triangle

x + 2 + x + 2 + x + 6 = 385
3x + 10 = 385
3x = 385 - 10
3x = 375
x = 375/3
x = 125

So the two equal sides = x + 2 = 125 + 2 = 127

The third side = x + 6 = 125 + 6 = 131

Perimeter = 127 + 127 + 131 = 385

Hence proved