Draw regular pentagon with side length given

Construct a Regular Pentagon of side 40 mm

The Video shows the step by step method to draw a Regular Pentagon 

Step by step guide to draw Regular Pentagon

1.  Draw line AB of length 40 mm ( first side of the Pentagon ABCDE )
2.  Draw circle with B as center and AB as radius- ( Ist circle )
3.  Draw another circle with A as center and AB as radius ( 2nd circle )
4.  Mark the points P & Q at the intersection points of the two circles
5.  Draw line PQ and extend towards up
6.  Draw circle with Q as center and QA or QB as radius ( 3rd circle )
7.  Mark the points F & G at the intersection points of the circles
8.  Mark the point S at the point of intersection of the circle with line PQ
9.  Draw line FS and extend till it intersect with the 2nd circle
10.Mark the point of intersection as C
11.Draw line BC ( 2nd side of the Pentagon )
12.Pick the length of line AB in compass and mark the point on the extended part of line PQ
13.Mark this point as D
14.Draw line CD ( 3rd side of the Pentagon )
15.Draw line GS and extend till it intersect with the Ist circle
16.Mark the point of intersection as E
17.Draw line DE ( 4th side of the Pentagon )
18.Draw line EA ( 5th side of the Pentagon )
19.Now you have drawn the Pentagon ABCDE of side length 40 mm