luas persegi panjang adl 51,2 dm dengwn perbandingan 5:4.tentukan keliling persegi panjang

langsung aja y

L = p × l
51,2 = 5a × 4a
51,2 = 20a²
2,56 = a²
√2,56 = a
1,6 = a

panjang = 5a = 5×1,6 = 8 dm
lebar = 4a = 4×1,6 = 6,4 dm

K = 2(p+l)
K = 2(8+6,4)
K = 2(14,4)
K = 28,8 dm

semoga berguna +_+

diket :
L = 51,2 dm²
p = 5
l = 4


ditanya : k = ?

jawab :
L = p . l
L = px . lx
51,2 = 5x . 4x
51,2 = 20x²
51,2/20 = x²
2,56 = x²
1,6 = x

jadi,
p = 5 . 1,6
p = 8 dm

l = 4 . 1,6
l = 6,4 dm

keliling =
2 (p + l)
2 (8 + 6,4)
2 (14,4)
28,8 dm