Question

triunghi abc ac=15 ab=12 bc=18

Answer 1

Răspuns:

Explicație pas cu pas:

1)

DE ||BC ⇒ ΔADE asemeneaΔ ABC

⇒AD/AB=AE/AC=DE/BC⇒ 8/12=AE/15=DE/18

AE= 8*15:12=10 cm

DE= 8*18:12=12 cm

P ADE=AD+DE+AE=8+12+10=30 cm

2)

CD||AB⇒ ΔPAB asemenea Δ PDC ⇒

⇒PD/PA=PC/PB=CD/AB ⇒ PD/PA=PC/PB=21/36=7/12

PD/PA=7/12

PD/PA-PD = 7/12-7⇒ PD/20= 7/5⇒ PD=20*7:5=28 cm

PA=AD+PD=20+28=48 cm

PC/PB=7/12⇒ PC/PB-PC=7/12-7 ⇒ PC/25=7/5⇒ PC=25*7:5=35cm

PB=PC+BC=35+25=60cm