Draw a line of 8 cm
Take a protector and open it upto 4 cm and cut an arc from one end of line 8cm
Cut another arc of 4cm from another end
Meat both arc
Join the intersection of arc with both point of 8cm line
First, a line should be drawn of length 8 cm. Then take a protractor should be taken and opened upto 4 cm. An arc should be cut from one end of the line that has been drawn by us. Then let another arc be cut of 4 cm from another end. Join both the arcs. Join the intersection point of arc with both the points of the line.