Construct an equilateral triangle, given its side and justify the construction.
Steps of construction:
Step 1: Draw a line segment AB = 4cm.
Step 2: Taking A and B as centres, make two arcs.
Step 3: With D and E as centres, make two arcs cutting the previous arcs respectively and forming an angle of 600 each.
Step 4: Extend the lines from A and B to intersect each other at C.
Thus, ABC is the required triangle formed