Question

Question
Which of the following expressions correctly shows the relationship between the circumference and the area of a circle?(1 point)
Responses

C2=4πA

upper C squared equals 4 pi upper A

Cd=π

Start Fraction upper C over d End Fraction equals pi

A=πr2

upper A equals pi r squared

C=2πr

Answer 1

C^2 = 4πA

Reason: C = 2πr, so r = C/(2π). Then A = πr^2 = π(C/(2π))^2 = C^2/(4π), which rearranges to C^2 = 4πA.