Question

Plissss bantu saya......... ...!

Answer 1

DB = x
 
AD / DE = AD+DB / BC
10 / 8 = 10+X / 12
10x12 = 8 (10+X)
120 = 80 + 8X
120-80 / 8 = X
40 / 8 = X
    X    =  5

X = DB = 5 cm

Answer 2

AD : AB = DE : BC
10 cm : AB = 8 cm : 12 cm
AB = AD * BC / DE
      = 10 cm * 12 cm / 8 cm
      = 15 cm
AB = AD + DB
15cm = 10cm + DB
DB = 15cm - 10cm = 5cm