Construct a regular hexagon of side 4.5 cm. Hence, construct a circle circumscribing the regular hexagon. Use ruler and compass for the construction. Measure and write down the radius of the circle.

164, 160, 156, 152, ….. are in Arithmetic Progression (A.P.). Find :

(a) which term is equal to 0.

(b) the sum of its first 20 terms.

In the adjoining figure of a circle with centre O and diameter AD, ∠BED = 70° and BC is parallel to AD. Find:

(a) ∠BAD

(b) ∠BOD

(c) ∠DBC

(d) ∠DCF