Jawabanmu

2014-01-17T18:21:02+07:00
Cari dulu r nya..
a. 3,14. r^2 =314
  r^2 = 314 / 3,14
r^2 = 100
r = 10 
kel = 2 * 3,14 *10
     = 62,8
b. 22/7 . r^2 = 616
r^2 =616 / 22/7
r^2 = 616 * 7/22
r^2 = 196
r = 14
kel = 2. 22/7 . 14
      =