Suatu persegi panjang kelilingnya 80 cm. Panjangnya ( 7×+8 ) cm dan lebarnya ( 3×+2 ) . Hitunglah luas persegi panjang itu !
pliss bantuin kak
QuizZ ✨✨
Jawaban:
K = 2p + 2l
80cm = 2(7x + 8) + 2(3x + 2)
= (14x + 16) + (6x + 4)
= 20x + 20
20x = 80cm – 20
20x = 60
x = 60/20 = 3
p = (7.3 + 8) = 29cm
l = (3.3 + 2) = 11cm
luas : 29cm x 11cm = 319cm²
Diketahui
P = 7x+8 = 7(3) + 8 = 21+8 = 29
L = 3x+2 = 3(3) + 2 = 11
K = 80
Ditanya : L = ?
Jawaban
K = 2p + 2l
80 = 2 (7x+8) + 2 (3x+2)
80 = 14x + 16 + 6x + 4
80 = 20x + 20
80 – 20 = 20x
60 = 20x
60 : 20 = x
3 = x
Jadi, x = 3
Jadi p = 7x+8 = 7(3) + 8 = 21+8 = 29
l = 3x+2 = 3(3) + 2 = 11
L = p x l
L = 29 × 11
L = 319
maaf kalo salah :))