Question

The perimeter of an isosceles triangle is 11 cm and base is 5 cm then prove area is 5/4square 11cmsquare

Answer 1

Perimeter of isosceles triangle = 2a+b = 11cm
base = 5cm
∴ perimeter = 2a+5 = 11
                  ⇒ 2a = 6
                  ⇒ a =3
According to Heron's formula,
s = a+b+c whole divided by 2
s = 3+3+5 /2 = 5.5 cm
area = √s(s-a)(s-b)(s-c)
= √5.5(5.5-3)(5.5-5)(5.5-3)
=√5*2.5*2.5*0.5
=√6.25
=2.5 cm²





Hope it helps... :)