Question

Find the area of an isosceles triangle with base $10cm$ and perimeter $36cm$

Answer 1

R.E.F image

Given : $BC=10cm,AB=AC$

perimeter $=36cm$

$AB+BC+AC=36cm$

$2AB=26cm$

$AB=AC=13cm$

semi-perimeter = $\frac{perimeter}{2}$

$S=\frac{36}{2}=18cm$

using Heuron's formula,Area of $△ABC$

$=\sqrt{S(S-a)(S-b)(S-c)}=\sqrt{18\left(8\right)\left(5\right)\left(5\right)}$

$=\sqrt{3\times 3\times 2\times 2\times 2\times 2\times 5\times 5}=\sqrt{(60{)}^2}$

$=60c{m}^2$