A sector of a circle of radius 7cm subtending an angle of 270° at the centre of the circle is used to form a cone. (a) Find the base radius of the cone. (b)...

A sector of a circle of radius 7cm subtending an angle of 270° at the centre of the circle is used to form a cone.

(a) Find the base radius of the cone.

(b) Calculate the area of the base of the cone to the nearest square centimetre.

[Take \(\pi = \frac{22}{7}\)]