Consider a circle. Answer the following questions about angles in a circle.
a. (i) Define a central angle and an inscribed angle of a circle.
b. (ii) Describe, with reason, how the measure of an angle subtended by a fixed arc at the centre compares with the measure of any angle subtended by the same arc at the circumference.
c. (iii) Give one real-life example where this comparison of angles can be useful.