If the perimeter of a semicircle is 108 cm, then find its area (in cmz).
Let radius of semi circle = $$r$$ cm
=> Perimeter of semi circle = $$\pi r+2r=108$$
=> $$r(\frac{22}{7}+2)=108$$
=> $$r(\frac{22+14}{7})=108$$
=> $$r=108\times\frac{7}{36}=21$$ cm
$$\therefore$$ Area of semi-circle = $$\frac{1}{2} \pi r^2$$
= $$\frac{1}{2}\times\frac{22}{7}\times(21)^2$$
= $$11\times21\times3=693$$ $$cm^2$$
=> Ans - (C)
Create a FREE account and get:
