Question

A circular disc of radius $10cm$ is divided into sectors with angles ${120}^o$ and ${150}^o$, then the ratio of the area of two sectors is

• A. $4:5$
• B. $5:4$
• C. $2:1$
• D. $8:7$

Answer 1

Answer: (A)

$4:5$

Area of sector formed from angle $\theta =\frac{\theta }{{360}^{\circ }}\pi r^2$, where $r$ is the radius of the circle
Now, if angle is ${120}^{\circ }$, ${150}^{\circ }$ then the ratio of area of sector will be

$\Rightarrow \frac{\frac{{120}^{\circ }}{{360}^{\circ }}\pi r^2}{\frac{{150}^{\circ }}{{360}^{\circ }}\pi r^2}$

$\Rightarrow \frac{4}{5}$

Hence, the required ratio is $4:5$.