Perhatikan gambar berikut ini ! Panjang AE = 3/4 DE. Keliling bangun ABCD adalah....

Berdasarkan Teorema Phytagoras,
Panjang DE^2 = CE^2 - CD^2
DE^2 = 13^2 - 5^2
DE^2 = 169 - 25
DE^2 = 144
DE = 12 cm

Maka panjang AE = 3/4 DE
AE = 3/4 × 12
AE = 9 cm

Panjang AD = BC
AD^2 = AE^2 + DE^2
AD^2 = 9^2 + 12^2
AD^2 = 81 + 144
AD^2 = 225
AD = 15 cm
BC = 15 cm

Keliling trapesium berarti semua sisi terluarnya dijumlahkan
= AB + BC + CD + AD
= (AE+BE)+BC+CD+AD
=9+14+15+5+15
= 58 cm

Kelilingnya = 58 cm
Smoga membantu :)

DAFTAR TRIPEL PHYTAGORAS:
• 5, 12, 13
• 3, 4, 5 = 9, 12, 15

Jadi,
DE = 12 cm

AE = 3/4 DE
AE = (3/4)(12)
AE = 9 cm

AD = 15 (tripel 9, 12, 15)

AD = BC
15 = 15

Keliling bangun ABCD
= AB + BC + CD + AD
= (AE + EB) + BC + CD + AD
= (9 + 14) + 15 + 5 + 15
= 23 + 35
= 58 cm