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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.
Solution
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
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