Area of the first circle = 16(pi) We know that Area of a circle = (pi) * (Radius)^2 Then 16(pi) = (pi) * (radius) ^2 (4)^2 = (Radius)^2 Radius = 4 Diameter = 8 Circumference = (pi) * Diameter = 8(pi) In case of the second circle Area = (pi) * (Radius) ^2 25(pi) = (pi) * (Radius)^2 (5)^2 = (Radius)^2 Radius = 5 Diameter = 10 Circumference = 10(pi) So Circumference of first circle:Circumference of second circle = 8(pi):10(pi) = 4:5
