Question

Find the diameter of a circle whose area is 394.24

Answer 1

area of circle = π(2r) = πd.....(1)

where d is diameter

and given area of circle = 394.24 ....(2)

compare (1) and (2)

πd = 394.24

d = 394.24/π

d = 394.24 * 7/22

d = 17.92 * 7

d = 125.44

Answer 2

area of circle =πr²

394.24 = 3.14r²

r² =125.544

r = 11.205 cm