Question

The perimeter of an isosceles triangle is 91 cm and its base is \(1 \frac{1}{4}\) times each of its equal sides. What is the length (in cm) of its base?
1. 20
2. 28
3. 35
4. 25

Answer 1

Correct Answer - Option 3 : 35

Given:

Perimeter of an isosceles triangle = 91cm

Formula:

Perimeter of an isosceles triangle = 2 × equal side + unequal side

Calculation:

⇒ Base = 5/4 × equal side

Then,

⇒ 91 = 2 × equal side + 5/4 × equal side

⇒ 13/4 × equal side = 91

⇒ Equal side = 28 cm

⇒ Base = 5/4 × 28 = 35 cm

∴ Length of base is 35cm.