If two sides of a triangle are 8 cm, and 11 cm and perimeter of triangle is 32 cm, then its area is:

b$=$ 11cm

perimeter $=$ p$=$ 32cm

$8+11+c=32$

$c=32-19=13$

$c=13$

$s=\frac{a+b+c}{2}=\frac{8+11+13}{2}$

$=\frac{32}{2}$

$=16$

$\therefore$ Area of $\Delta$ $s=\frac{a+b+c}{2}=\frac{8+11+13}{2}$

$=\sqrt{s\left(s-a\right)\left(s-b\right)\left(s-c\right)}$

$=\sqrt{16\times \left(16-8\right)\times \left(16-11\right)\times \left(16-13\right)}$

$=\sqrt{16\times 8\times 5\times 3}$

$=8\sqrt{30}{\text{ cm}}^2$