Question

Keliling sebuah persegi panjang 80 cm. Jika perbandingan panjang dan lebarnya 5:3 maka luasnya adalah...................cm²

tlong dikerjakan menggunakan cara


THANKS

Answer 1

Keliling = 2 (p+l)
80 = 2 (p+l)
80/2 = p + l
40 = p + l

p:l = 5 : 3
p = 40/(5+3) × 5
p = 40/8 x 5
p = 5 x 5
p = 25
l = 40/(5+4) ×3
l = 40/8 x 3
l = 5 x 3
l = 15

pembuktian:
kll = 2 x (p+l)
80 = 2 x (15+25)
80 = 2 x 40
80 = 80

luas
= p x l
= 15 x 25
= 375 cm²

Answer 2

Keliling = 80 cm
p:l = 5:3
p+l = 40 cm
p = 5/8 × 40
= 25 cm
l = 3/8 × 40
= 15 cm
L = p×l
= 25 × 15
= 375 cm2