a ) Diameter = 10 radius =10 / 2 = 5
Area = pi * radius ^2 = pi * 5^2 = 25 pi
b ) Area of AOB ....this is a right triangle with legs AO =AB = 5
Area = (1/2) (prdict of the legs) = (1/2) (5 * 5) = 25 /2
c ) COD has same area as AOB
d ) Area of shaded region = area of circle -[ AOB ] -[ COD = 25pi - 25/2 -25/2 = 25pi - 25 = 25 [ pi -1 ]
e ) AB is the hypotenuse of an isosceles right triangle....its length = leg length * sqrt (2) =
5sqrt (2) ≈ 7.1