hitunglah keliling yang diarsir

2.
K = (1/2 x 2 x pi x r) +  2r
   = (22/7 x 7) + (2 x 7)
   = 22 + 14
   = 36 cm

3.
K = (1/4 x 2 x pi x r) + r + r
    = (1/2 x 3.14 x 10) + 10 + 10
    = 15,7 + 20
    = 35,7 cm