Construct an Equilateral Triangle:
To Construct an Equilateral Triangle when the Length of the Side is given
Employ a T-square and a set-square only. Along with a T-square, draw a line AB of the given length. By using a set-square with angles of 30o - 60o and a T-square, draw a line by A making 60o angle along with AB. Similarly, via B, draw a line making the same angle (60o) along with AB and intersecting the first line at C. ABC is the required triangle.
For Constructing an Equilateral Triangle of a Given Altitude
Along with a T-square, draw a line AB of any length. From a point P on AB, draw, along with a set-square, vertical PQ equal to the given altitude. Along with T-square and
30o - 60o set square, draw lines via Q on both sides, making 30o angle along with PQ and cutting AB at R and T. QRT is the essential triangle.