Question

Find area of an isosceles triangle whose perimeter is 50m and the unequal side is 10m.

Answer 1

Perimeter =50 m
unequal side =10 m
$\therefore$ length of equal side =$\frac{50-10}{2}=20m$
s =25
Area =$\sqrt{s(s-a)(s-b)(s-c}$
$=\sqrt{25(25-20)(25-20)(25-10)}$
$=\sqrt{25\times 5\times 5\times 15}=5\times 5\sqrt{15}=25\sqrt{15}{m}^2$