suatu persegi panjang memiliki ukuran panjang (4p+7) cm dan lebar (3p+3)cm.Jika kelilin persegi panjang tsb 90cm,luasnya adalah...

90 = 2(4p+7 + 3p+3)
90 = 2× 7p +10
90 = 14p +20
90-20 = 14p
70 = 14p
p = 5

panjang = (4×5)+7
= 27

lebar = (3×5)+3
=18

luas = p×l
27×18
=486cm^2

K=2(p+l)
90=2(4p+7+3p+3)
90=8p+14+6p+6
90=14p+20
70=14p
5=p
p=4p+7
p=4(5)+7
p=27
l=3p+3
l=3(5)+3
l=18
Luas=p.l
=27.18
=486 cm²