When the Three Lengths Are Known (3-4-5)

1. Draw a line equal to one of the known lengths.
2. Set your compass to the second known length (6 inches) and swing an arc from one end of the line (point A).
3. Set your compass to the third known length (3 inches) and swing an arc from the other end (point B) of the line, crossing the first arc.
4. Complete the triangle by drawing two lines from the ends (points A and B) of the line to the cross point of the two arcs.