Question

Answer this properly with clear steps pls. (The circle sum)

Answer 1

see in the given figure we know the perimeter by this we can find the radius 
so 2 x pi x r = 40
2 x 22/7 x r = 40
44/7 x r = 40 
r= 280/44
simplifying we get r = 70/11
now one quadrant is taken out so Ф = 360°-90°⇒ 270°( (the angle made by the radius is 270°)
Ф/360 x 2 x pi x r ⇒ 270/360x 2 x 22/7 x 70/11
simplifying , we get it 15 cm²