tlg dijawab ya pakai caranya no 10 jk terimakasih

Kesebangunan
Matematika IX

a. BC
Keliling segitiga = 20 cm
BC + AB + AC = 20 cm
BC + 8 + 5 = 20
BC = 7 cm

b. AE
AE / AB = DE / CB
AE / 8 = 3,5 / 7
AE = ⁸/₂
AE = 4 cm

c. AD / AC = DE / CB
AD / 5 = 3,5 / 7
AD = ⁵/₂
AD = 2,5 cm