Question

Perbandingan panjang dan lebar kebun berbentuk persegi panjang 8 : 5. jika kelilingnya 78 m,maka luasnya adalah ......
a.180 m
b.360 m
c.480 m
d. 720 m

Answer 1

Kell = 2(p+l)
78 = 2(p+l)
78/2 = p +l
p + l = 39

panjang = 8/8+5 x 39
= 8/13 x 39
= 24 cm
lebar = 5/13 x 39
= 15 cm
luas = pl
= 24 x 15
= 360 m^2 (B)

Answer 2

P = 8x
l = 5x
K = 2(p + l) = 78
= 2(8x + 5x) = 78
8x + 5x = 39
13x = 39
x = 3
p = 8(3) = 24 m
l = 5(3) = 15 m
Luas = p × l = 24 × 15 = 360 m2