Question

Persegi panjang
keliling=360cm
panjang=(6x+8)cm
lebar=(2x+12)cm
hitunglah lebar,panjang dan luasnya!
pakai cara nya ya! tolong dibantu

Answer 1

K = p + p + l + l = 2(p+l)
360 = 2 ((6x+8)+(2x+12))
360 = 2 ( 6x+8+2x+12)
360 = 2 ( 8x + 20)
180 = 8x + 20
180-20 = 8x
160 = 8x
x = 160:8 = 20

panjang = 6x+8 = 6(20)+8 = 128
lebar = 2x+12 = 2(20)+12 = 52

luas = p × l = 128 × 52 = 6656

Answer 2

P = (6x + 8) cm
l = (2x + 12) cm
maka
K = 360 cm
⇒ 2(p + l) = 360
⇒ p + l = 180
⇒ 6x + 8 + 2x + 12 = 180
⇒ 8x + 20 = 180
⇒ 8x = 160
⇒ x = 160/8
⇒ x = 20 cm
maka

p = 6x + 8 ⇒ p = 6(20) + 8 ⇒ p = 120 + 8 ⇒ p = 128 cm
l = 2x + 12 ⇒ l = 2(20) + 12 ⇒ l = 40 + 12 ⇒ l = 52 cm

dan
L = p · l
⇒ L = 128 · 52
⇒ L = 6.656 cm²

Terimakasih semoga membantu