Question

Keliling suatu persegi panjang 42 cm . jika panjang : lebar = 4:3 maka luasnya adalah

Answer 1

42= 2(7x)
21=7x
x=3

p= 4(3)=12 dan l= 3(3)= 9

L= 12*9= 108cm^2

Answer 2

Kel = 2(p + l)
42 = 2(4x + 3x)
42 = 2 * 7x
42 = 14x
42 / 14 = x
3 = x

panjang = 4x = 4 * 3 = 12
lebar = 3x = 3 * 3 = 9
L = p * l
   = 12 * 9
   = 108 cm²