Question

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

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

Answer 1

The correct option is A 4 : 5

Now $\frac{c}{circle}=\frac{120}{360}=\frac{1}{3}$

And $\frac{c}{circle}=\frac{150}{360}=\frac{5}{12}$

So sector with angle 120 and 150 is part $\frac{1}{3}$ and $\frac{5}{12}$

Now ratio of the area of two sectors =Ratio of central angle =120:150=4:5