Jawabanmu

2014-04-29T19:13:54+07:00
R = 17 cm
r = 13 cm
d = 40 cm
p² = d² + (R+r)²
  = 40² + (17 + 13 )²
  =1600 +30²
  = 1600 + 900
  =2500
p = √2500
p = 50 cm