Keliling bangun adalah..

8 + 8 + 12 + 12 + 4 + 4 + 5 + 5 = 58
.
.
12 ÷ 3 = 4
.
58 + 4(4)
58 + 16 = 74 cm

8 x 2 =16
12 x 2 =24
4 x 2 =4
5 x 2 =10

trus di jumlah jadi 58
12 : 3 =4
58+ 4 x 4
=58 + 16 =74 cm