Angle an angle is a figure formed by two rays with the same initial point.

The figure formed by two rays with the same initial point is know as (a) a ray (b) a line (c) an angle (d) a line segment

The figure formed by two rays with the same initial point is know as a ray (b) a line (c) an angle (d) a line segment

The front angle formed at the centre of a circle by an are is half of the angle fromed by the same are at any point on the circle.

ANGLES AT A POINT Angles formed by a number of rays having a common initial point are called angles at a point.

Prove that the front angle formed at the centre of a circle by an arc, is double of the angle formed by the same arc at any point on the circle.

Complete angle if a rotating ray after making a complete revolution coincide with the initial position the angle formed is called a complete angle.

A ray of light falls on a glass slab making an angle of 45^(@) with normal. The emergent ray makes the same angle with normal. It shows that