jawab y yang jawab masuk surga

Semoga bermanfaat (:

a. k = pi x d                       b. k = pi x d              
       = 22/7 x 42                        = 22/7 x 63
       = 22 x 6                             = 22 x 9
       = 132 cm                           = 198 cm

c. k = 2 x pi x r                   d. k = 2 x pi x r
       = 2 x 22/7 x 28                   =2 x 22/7 x 12
       = 2 x 22 x 4                        =528/7
       = 176 cm                            =75,28 cm

ma'af ya kalau salah :-)