Question

The perimeter of an isosceles triangle is 42 cm and its base is $1\frac{1}{2}$ times its congruent sides. the length of congruent sides of the triangle

Answer 1

Let the congruent sides of the isosceles triangle $=a$ and the base $=b$.
Given, $b=1\frac{1}{2}\times a=\frac{3}{2}\times a$

Perimeter of the triangle $=$ Sum of all sides $=$ a
$\therefore a+a+b=42$

$2a+\frac{3}{2}\times a=42$

$\frac{7}{2}a=42$

$\therefore a=12cm$