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BUKU DIGITAL MATEMATIKA
B A N G U N D A T A R

B A N G U N D A T A R

JAJAR GENJANG & TRAPESIUM

Perhatikan gambar berikut!

Jika AB = 20 cm, BC = 12 cm, BE = 16
dan DC = (2x + 4) cm,

maka tentukan!

a. Nilai x
b. Panjang DC

c. Keliling jajargenjang ABCD

d. Luas Jajargenjang ABCD

Alternatif Penyelesaian

a. AB = DC, maka c. AB = CD = 20

20 = 2x + 4 BC = AD = 12, maka
20 – 4 = 2x K = 2AB + 2BC

16 = 2x = 2×20 + 2×12

6
= x = 40 + 24 K
2 = 64 cm
x = 8

b. DC = 2x + 4 dan x = 8, maka d. BC = AD = 12, maka

DC = 2(8) + 4 L = alas × tinggi
= 16 + 4 = AD × BE

DC = 20 = 12 × 16
2
L = 192

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