Construct a perpendicular to a line from a point on it.
                   
Here, \(\angle\)PAR = 90^o.

We know that, perpendicular bisector of a line segment is its axis of symmetry.
Step I Draw a line segment \(\bar{PQ}\) = 7 cm.
Step II With P and 0 as centres and radius more than half of \(\bar{PQ}\), draw two arcs which intersect each other at A and B.
                        
Step III Join A and B.
Thus, AB is the axis of symmetry of \(\bar{PQ}\).

Steps of construction are as follows:
Step I Draw \(\bar{PQ}\) of length 4 cm.
                     
Step II Draw a line l and mark a point R on it.
Step III Open the compasses equal to \(\bar{PQ}\).
Step IV Keeping the same opening. Place the pointer on R and mark a point S on I. Thus, \(\bar{RS}\) is a equal to \(\bar{PQ}\).
                    

Diameter

To draw two circles such that each one of them passes through the centre of the other, we use the following steps:
Step I Firstly, mark two points A and B on the paper.
Step II Take the distance between A and B as radius and draw a circle with centre A.
Step III Now, take B as centre and draw a circle with radius AB.
Thus, we get two circles which passes through the centres of each other. Let these circles intersect each other at C and D. Join C and D, which intersect AB at O. Then, we observe that, the \(\angle\)AOC and \(\angle\)COB are equal to 90°.
                         
Hence, \(\bar{AB}\bot\bar{CD}\)
So, we can say that \(\bar{AB}\) and \(\bar{CD}\) are at right angles.

Divider.

One

BD = DC.

AB = 3 BC.

3 cm.

Here, to divide an angle of measure 153° into four equal parts, we use the following steps:
Step I Draw \(\bar{AB}\) of any length. Place the centre of the protractor at A and the zero edge along \(\bar{AB}\).
Step II Start with zero near B. Mark point C at 153°.
Step III Join AC, then \(\angle\)BAC is an angle of measure 153^o.
                    
Step IV With A as centre and using compasses, draw an arc that cuts both rays of \(\angle\)A at P and Q.
                    
Step V With P as centre, draw (in the interior of \(\angle\)A) an arc whose radius is more than half the length of PQ.
                     
Step VI With the same radius and with Qas centre, draw another arc in the interior of \(\angle\)A. Let the two arcs intersect at D. Join \(\bar{AD}\). Let AD cut the arc PQ at I. Then, \(\bar{AD}\) divides the \(\angle\)BAC in two equal parts.
                    
Step VII Now, with P and I as centre and with radius more than half of length PI, draw two arcs respectively, which cut each other at R.
Step VIII Join \(\bar{AR}\) . Then, \(\bar{AR}\) divides \(\angle\)BAD into two equal parts.
Step IX Now, with Q and I as centre and with radius more than half of length QI, draw two arcs respectively, which cut each other at M.
Step X Join \(\bar{AM}\) . Then, \(\bar{AM}\) divide \(\angle\)CAD into two equal parts.
                       
Thus, \(\bar{AM},\bar{AD}\) and \(\bar{AR}\) divide  BAC into four equal parts.

To find out the axis of symmetry of \(\bar{AB}\) of length 7.3 cm, we use the following steps:
Step I Draw a line segment \(\bar{AB}\) of length 7.3 cm.
                   
Step II With A as centre, using compasses, draw a circle, whose radius is more than half the length of \(\bar{AB}\).
                     
Step III With the same radius and with B as centre, draw another circle using compasses. It cut the previous circle at C and D.
                    
Step IV Join \(\bar{CD}\) . It cuts \(\bar{AB}\) at O.
Then, \(\bar{CD}\) is the perpendicular bisector of AB.
Also, it is the axis of symmetry.

A chord of a circle divides the circle into two parts, where each part is called a segment of the circle.