Question

In fig6.18, if LM || CB and LN||CD,prove that AM/AB=AN/AB

Answer 1

Consider ∆ABC,

Angle ALM = Angle ACB

Angle A = Angle A ( Common)

Angle AML = Angle ABC

So The sides opposite to equal angles will be similar

AM/AB

Consider ∆ABC and ∆ADC,

AM=AN(angles are equal)

So AB=AD

Like in ∆ABC,

Consider ∆ADC,

We Get

AN/AD

Since ∆ABC = ∆ADC

AM/AB=AN/AD

AM/AB=AN/AB(AD=AB)

Proved....