Question

10. 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

11. A car has two wipers which do not overlap. Each wiper has
a blade of length 25 cm sweeping through an angle 115
Find the total area cleaned at each sweep of the blades.
12. To warn ships for underwater rocks, a lighthouse spreads a
red coloured light over a sector of angle 80° to a distance of
16.5 km. Find the area of the sea over which the ships are
warned. (Use 3.14)​

Answer 1

Answer:

area between the 2 ribs = 360/8=45

if the umbrella is a flat circle

area= 45/360 *22/7*45*45=795 cm^2