In the given fig., D is a point on hypotenuse AC of ∆ABC, DIM ⊥ BC and DN ⊥ AB.Â
Prove that:
(i) DM2 = DN × MC.
(ii) DN2 = DM × AN.
In the given fig., ABC is a triangle in which ∠ABC > 90° and AD ⊥ CB produced. Prove that AC2 = AB2 + BC2 + 2 BC . BD.
In the given Fig,  ABC is a triangle in which ∠ABC < 90° and AD ⊥ BC. Prove that AC2= AB2 + BC2 - 2 BC.BD.
In the given fig, AD is a median of a triangle ABC and AM ⊥ BC. Prove that:
(i) Â Â
(ii)Â
(iii) Â Â
In the given fig, two chords AB and CD intersect each other at the point P. Prove that:
(i) ∆APC ~ ∆DPB.
(ii) AP . PB = CP . DP
In the given Fig, two chords AB and CD of a circle intersect each other at the point P (when produced) outside the circle. Prove that
(i) ∆PAC ~ ∆PDB.
(ii) PA. PB = PC . PD.
In the given fig, D is a point on side BC of ∆ABC such that   Prove that AD is the bisector of ∠BAC.
∵    AC = AE [By construction]
∴    ∠3 = ∠4    ...(iii)[Angles opposite equal sides of a triangle are equal]
Using (iii), (i) and (ii), we get∠BAD = ∠CAD
Hence, AD is the bisector of ∠BAC.