Question

Keliling suatu persegi panjang 80 cm. Jika perbandingan panjang dan lebarnya 7:3 maka luas persegi panjang tersebut adalah?
Tolong jawab pake caranya ya. Makasih

Answer 1

P:l = 7:3
p:l = 7x:3x

K = 80
2×(p+l) = 80
7x+3x = 80:2
10x = 40
x = 40:10
x = 4

p = 7x
p = 7×4
p = 28 cm

l = 3x
l = 3×4
l = 12 cm

L = p×l
L = 28×12
L = 336 cm2

Answer 2

K = 2 (p+l)
80 = 2 (7x + 3x)
40 = 10x
4 = x

p = 7x4 = 28
l = 3x4 = 12

Luas = 28 x 12 = 336.