Jika luas layang-layang PQRS =168cm2 PT : TR = 2 : 5 Dan QS = 16cn .Hitunglah keliling layang layang

LAYANG LAYANG

d1 = PR => PT : TR = 2 : 5

d2 = QS = 16 cm

cari dulu d1 :
Luas = 168
1/2 × d1 × d2 = 168
1/2 × d1 × 16 = 168
d1 × 8 = 168
d1 = 168/8
d1 = 21 cm

d1 = 21 cm
PT + TR = 21 cm

sedangkan PT : TR = 2 : 5

gunakan konsep perbandingang :

PT = 2/(2+5) × 21 = 2/7 × 21 × 2×3 = 6 cm
TR = 21 - 6 = 15 cm

sekarang cari sisi PQ dan QR
PQ^2 = 6^2 + (1/2 × 16) = 36 + 64 = 100
PQ = akar100
PQ = 10 cm

QR^2 = 15^2 + (1/2 × 16)^2 = 225 + 64 = 289
QR = akar289
QR = 17 cm

Keliling = 2×(PQ+QR)
keliling = 2×(10+17)
keliling = 2×27
keliling = 54 cm

smg membantu