If the sides of a triangle are 11 cm, 60 cm and 61 cm, then

Area of triangle $=\sqrt{s(s-a)(s-b)(s-c)}$

$s=\frac{a+b+c}{2}=\frac{11+60+61}{2}=\frac{132}{2}=66$

$\Delta =\sqrt{66(66-11)(66-60)(66-61)}$

$\Delta =\sqrt{66\left(55\right)\left(6\right)\left(5\right)}$

$=\sqrt{6\times 11\times 5\times 11\times 6\times 5}$

$=\sqrt{{(6\times 5\times 11)}^2}$

$=6\times 5\times 11$

$=330c{m}^2$

Perimeter of triangle $=$ Sum of all sides

$=11+60+61$

$=132cm$

(or)

$\frac{1}{2}\left(BC\right)\times \left(AB\right)$

$=\frac{1}{2}\left(60\right)\times 11$

$=330c{m}^2$