Question

Each of the 2 equal sides of an isosceles triangle is twice as large as the third side. If the perimeter of the triangle is 30 cm, find the length of each side of the triangle.

• A. 6, 10, 10
• B. 6, 12, 12
• C. 4, 10, 10
• D. 4, 12, 12

Answer 1

The correct option is B 6, 12, 12

Let the length of the third side be $x$ cm.
Each equal side = $2x$ cm.

As per the condition of the question, we have
Perimeter = $x$ + $2x$ + $2x$ = 30
⇒ $5x$ = 30
⇒ $x$ = 6

Thus, the third side of the triangle = 6 cm and other two equal sides are 2 × 6 = 12 cm each