Question 34877
CIR=2*PI*R OR 20*PI=2*PI*R DIVIDING BOTH SIDES BY 2*PI WE GET R=10

CIR=2*PI*R OR 64*PI=2*PI*R DIVIDING BOTH SIDES BY 2*PI WE GET R=32

AREA=PI*R~2 OR 9*P1=PI*R~2 DIVIDING BOTH SIDES BY PI WE GET R~2=9 OR R=3

AREA=PI*R~2 OR 64*PI=PI*R~2 DIVIDING BOTH SIDES BY PI WE GET R~2=54 OR R=8