keliling 30m panjang 8m luas nya

Keliling = 2p + 2L
30m = 2 x 8m + 2L
30m = 16m + 2L
30m -16m = 2L
14m = 2L
7m = L

Luas :
= Panjang x Lebar
= 8M x 7M
= 56m²

kel = 30 m
P = 8 m
l = keliling ÷ 2 - P = 30 ÷ 2 - 8 = 15 - 8 = 7 m
Luas = P × l = 8 × 7 = 56 m²