Two points A and B lie on the same side of a line XY. If AD ⊥ XY and BE ⊥ XY meet XY in D and E respectively and C is the mid-point of AB, show that CD = CE.

Prove that the straight lines joining the mid-points of the opposite sides of a quadrilateral bisect each other.

ABC is a right angled isosceles triangle in which ∠A = 90°. If D and E are the mid-points of AB and AC respectively, then ∠ADE =

1. 30°

2. 45°

3. 60°

4. 90°

On the sides AB and AC of a △ABC, D and E are two points such that AD : AB = AE : AC = 1 : 2. If BC = 7 cm, then DE =

1. 3.5 cm

2. 7 cm

3. 14 cm

4. 15 cm