Question

Question 77

Draw an angle of ${140}^{\circ }$ with the help of a protractor and bisect it using ruler and compass.

Answer 1

The bisector of an angle is a ray whose end point is the vertex of the angle and which divides the angle into two equal angles.

Steps of construction:

Step I: Draw an angle $\angle B={140}^{\circ }$

Step II: With B as a centre and using a compass, draw an arc which cuts both rays of $\angle B$ at A and C.

Step III: With A as centre, draw (in the interior of $\angle B$ an arc whose radius is more than half the length of AC

Step IV: With C as centre and with the same radius and draw another arc, in the interior of $\angle B$ let the two arcs intersect at D. Then $\overline{BD}$ is the required bisector of $\angle B$.