Question

Find the area of an isosceles triangle whose equal sides are $5cm$ and base is $8cm$.

Answer 1

Altitude $=\sqrt{5^2-4^2}=3$

Area $=\frac{1}{2}\left(base\right)\left(height\right)$

$=\frac{1}{2}\times 8\times 3=12c{m}^2$.