Question

If a pizza having radius of 21 cm is divided into 9 equal parts, then find the area of one sector(slice) thus formed and the angle subtended at centre.

• A. 77 $c{m}^2$, ${45}^0$
• B. 154 $c{m}^2$, ${40}^0$
• C. 231 $c{m}^2$, ${45}^0$
• D. 441 $c{m}^2$, ${40}^0$

Answer 1

The correct option is B 154 $c{m}^2$, ${40}^0$

As pizza is circular in shape, each divided part is in shape of a sector.

Area of sector = $\frac{1}{9}$$\times$$\pi$$r^2$
= $\frac{1}{9}$$\times$$\frac{22}{7}$$\times$${21}^2$
= $\frac{1}{9}$$\times$$\frac{22}{7}$$\times$441
= 154 $c{m}^2$

Angle subtended at the center = $\frac{1}{9}$$\times$${360}^0$ = ${40}^0$