Question

In the given figure, radius of the circle is 7 cm and m ( arc MBN) = 60^°,

find (1) Area of the circle .

(2) A(O - MBN) .

(3) A(O - MCN) .

Answer 1

Radius of the circle, r = 7 cm

m(arc MBN) = ∠MON = θ = 60º

(1)
Area of the circle = $\mathrm{\pi }{r}^2=\frac{22}{7}\times {\left(7\right)}^2$ = 154 cm²

(2)
A(O-MBN) = Area of the sector OMBN = $\frac{\theta }{360°}\times \mathrm{\pi }{r}^2=\frac{60°}{360°}\times \frac{22}{7}\times {\left(7\right)}^2$ = 25.7 cm²

(3)
A(O-MCN) = Area of the sector OMCN

= Area of the circle − Area of the sector OMBN

= 154 − 25.7

= 128.3 cm²