An umbrella has 8 ribs which are equally spaced (as shown in the figure).Assuming the umbrella to be a flat circle of radius 42 cm, find the area between the two consecutive ribs of the umbrella.

Explanation

Since the ribs are equall spaced, so the angle by two consecutive ribs at the centre `=(360/9)^(@)=45^(@)`
Area between two consecutive ribs
`=` area of a sector of a circle with `r=42cm` and `theta=45^(@)`
`=(45/360xx22/7xx42xx42)cm^(2)`
`=693cm^(2)`