Question

Two concentric circle with center O have radii 21cm & 42cm .if angle AOB=60° Find the area of the shaded region

Answer 1

area of the ring = π (42² - 21²) = 4158 cm²

now, we have to remove some parts,

that part = (sector formed by bigger circle) -( sector formed by smaller circle)

             =π (42)²×60°/360 -π(21)² ×60°/360°

             =(π/6)×(42² -21²) = 693 cm²

so the required area = 4158 - 693 = 3465 cm²

see, if small part is shaded then the answer is 693 cm² otherwise if red shaded region you wanna then above answer is correct.

Answer 2

Answer:

area of big circle =1/6×π×r×r

=231.

area of small circle 924

as per your westion. ashaded region is there but you haven't mentioned which is the sahded portion so use this values