27a. Construct a Triangle Given a Side, the Length of the Altitude to It and the Opposite Angle
This Demonstration constructs a triangle given the length of the base , the angle at and the length of the altitude from to the base.[more]
1. Draw a line segment of length .
2. Draw the point so that the angle equals and . Draw the circle with center through and .
3. Draw a line parallel to at distance . The third point of the triangle is the intersection of and .
The angle at is , since the central angle that subtends equals .[less]
This construction was taken from .
 G. Polya, How to Solve It: A New Aspect of Mathematical Method, 2nd ed., Princeton, NJ: Princeton University Press, 1957.