Draw an angle and label it as ∠BAC. Construct another angle, equal to ∠BAC.

The steps of the required construction are:

1) Draw an arbitrary angle ∠BAC.

2) Taking A as the center and any radius draw an arc which intersects AB and AC at point D and E respectively.

3) Draw a line segment QR of arbitrary length. With Q as the center and Radius AD, draw a circular arc, intersecting QR at S.

4) Taking S as the center and radius DE, draw another circular arc, intersecting the previous arc at P. Join QP.

5) ∠RQP=∠BAC