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?
Answer & explanation
Correct answer: option 1
We know that,
Perimeter of an isosceles triangle = 2 × equal side + unequal side
Perimeter of an isosceles triangle = 91cm
Given = Base = \(\frac{5}{4}\)× equal side
Then,
= 91 = 2 × equal side + \(\frac{5}{4}\)× equal side
= $\frac{13}{4}$ × equal side = 91
= Equal side = 28 cm
= Base = \(\frac{5}{4}\)× 28 = 35 cm