Q

# The diameter of a circle is a line which joins two points on the circle and also passes through the centre of the circle. (In the adjoining figure (Fig 11.12) AB is a diameter of the circle; C is its centre.)

Q. 4.     The diameter of a circle is a line which joins two points on the circle and also passes through the centre of the circle. (In the adjoining figure (Fig 11.12)$\inline AB$  is a diameter of the circle; $\inline C$ is its centre.) Express the diameter of the circle $\inline (d)$ in terms of its radius $\inline (r).$