Question

An umbrella has 8 ribs which are equally spaced. Assuming umbrella to be a flat circle of radius 45 cm. Find the area between the two consecutive ribs of the umbrella.

Answer 1

Since ribs are equally spaced. Therefore, Angle made by two consecutive ribs at the centre = `\frac { 360° }{ 8 } = 45º`

Area of sector = `theta/(360º) xx pir^2`

`= (45º)/(360º) xx 22 /7 xx 45xx45`

`= (11 xx 45xx 45)/(4xx7)`cm²

`= 22275/28` cm²

The required area between the two consecutive ribs `= 22275/28` cm²