c)
BD = 4/5 cm
AD =2,4
In ∆ABC dr=>T. In AD²= BD×CD
2,4²=4/5×CD
CD = 5,76:4/5
CD=7,2 cm
BC = CD×DB = 7,2+4/5 =8 cm
4.
a)
BD=2√3
BC=8√3
BC = CD+DB =>CD= 8√3-2√3 =6√3
In ∆ABC dr=>T. In AD² =CD×DB
AD²= 6√3×2√3
AD² = 36
AD=√36
AD=6 cm
b) AD=6 cm
BD =4 cm
In ∆ABC dr=>T. In AD² = CD×BD
6²=CD× 4²
CD= 36:16
CD = 2,25
c)
AD=3√3
DC=3 cm
In ∆ABC dr =>T. In AD² =CD×BD
(3√3)²=3×BD
BD = 27:3
BD = 9 cm
