Construct an equilateral triangle whose altitude is 3.5 cm
1-Firstly draw a line PQ of any measure and on this line draw prpendicular on it. Now take the measure of altitude on ur compass and cut an arc on the perpendicular line.where it cuts make angles of 30degree both sides and join these angles on PQ line.Now the required triangle is formed.
Draw a line XY. Take any point D on this line. Construct perpendicular PD