Question

An umbrella has 8 ribs which are equally spaced. Assuming the umbrella to be a flat circle of radius 42 cm, find the area in $c{m}^2$ between the two consecutive ribs of the umbrella.

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Answer 1

Radius = 42 cm

8 ribs implies angle subtend between consecutive ribs = $\frac{360}{8}$ = ${45}^{\circ }$ .

Area between consecutive ribs = $\frac{\theta }{360}\times \pi \times (radius{)}^2$
$\frac{45}{360}$ × $\frac{22}{7}$ × ${42}^2$ = 693 $c{m}^2$