Question 22

The area of a semicircle is 1925 cm2. Calculate its perimeter (in cm).

Solution

Let radius of the semi-circle = $$r$$ cm

=> Area = $$\frac{1}{2}\times\pi r^2$$=1925$$

=> $$\frac{1}{2}\times\frac{22}{7}\times r^2=1925$$

=> $$r^2=1925\times\frac{7}{11}=1225$$

=> $$r=\sqrt{1225}=35$$ cm

$$\therefore$$ Perimeter = $$\pi r+2r$$

= $$(\frac{22}{7}\times35)+(2\times35)$$

= $$110+70=180$$ cm

=> Ans - (D)

Share on Whatsapp Share on Whatsapp

Create a FREE account and get: