keliling bangun diatas adalah?

K = ( 5 x 5 cm) + (4 x 10 cm) + 15 cm
    = 25 cm + 40 cm + 15 cm
    = 80 cm

Tanda = :10
Tanda - :15-10=5
Kll = 10(4) + 5(5) + 15
Kll = 40 +25 +15 = 80 (c)