In the given figure, AB and AC are equal chords of a circle with centre O and OP ⟂ AB, OQ ⟂ AC. Prove that PB = QC.

In an equilateral triangle, prove that the centroid and the circumcentre of the triangle coincide.

A chord of length 40 cm is drawn at a distance of 15 cm from the centre of a circle, then the radius of the circle will be :

1. 12 cm

2. 15 cm

3. 17 cm

4. 25 cm

In the figure, O is the centre of the circle and AC = BC = 3.5 cm. ∠ACO will be :

1. 60°

2. 80°

3. 90°

4. 100°