Question

OACB is a quadrant of a circle with centre O and its radius is 3.5 cm. If OD = 2 cm. find the area of

1. the quadrant OACB 
2. the shaded region.
   [Take `π = 22/7`.]

Answer 1

i . Area of the quadrant OACB `=(1/4xx22/7xx3.5xx3.5) "cm"^2 `

`=(1/4xx22/7xx35/10xx35/10) "cm"^2`

`=77/8  "cm"^2`

= 9.625 cm² 

ii . Area of the shaded region = Area of the quadrant OACB -  Area of ΔAOD 

`=|(77/8)- (1/2xx3.5xx2)|"cm"^2`

`= (77/8 - 35/10) "cm"^2 `

`=49/8 "cm"^2`

= 6.125 cm²