In the given figure, OD = 2 × OB, OC = 2 × OA and CD = 2 × AB then △ AOB ~ △ COD by :

1. AA

2. SS

3. SAS

4. SSS

Are the two congruent triangles always similar?

1. yes

2. no

3. none of these

Sides AB, BC and median AD of the triangle ABC are respectively proportional to sides PQ, QR and median PM of triangle PQR.

Prove that:

(i) Δ ABD ∼ Δ PQM

(ii) Δ ABC ∼ Δ PQR