Diketahui keliling persegi panjang adalah 20 m. Jika sisi terpanjangnya (5x – 3) m dan sisi lainnya (3x – 1) m, Tentukan

Penjelasan dengan langkah-langkah:

a. Keliling (K) = 2(p + l)

p = panjang

l = lebar

20 = 2(5x – 3 + 3x – 1)

10 = 8x – 4

14 = 8x

x = 14/8 = 7/4

b. p = 5x – 3

= 5(7/4) – 3

= 35/4 – 3

= (35 – 12)/4

= 23/4

l = 3x – 1

= 3(7/4) – 1

= 21/4 – 1

= (21 – 4)/4

= 17/4

Menentukan nilai x!

K = 2(p + l)

20 = 2((5x – 3) + (3x – 1))

20/2 = 5x – 3 + 3x – 1

10 = 5x + 3x -3 – 1

10 = 8x – 4

8x = 10 + 4

8x = 14

x = 14/8

x = 1,75

Menentukan panjang:

p = (5x – 3) m

p = (5(1,75) – 3) m

p = (8,75 – 3) m

p = 5,75 m

.

Menentukan lebar:

l = (3x – 1) m

l = (3(1,75) – 1) m

l = (5,25 – 1) m

l = 4,25 m