Special Triangles

This enrichment activity looks at three special types of triangles with side lengths that are all whole numbers. One type of triangle has a 60° angle. Another type has a 120° angle.

For the third type of triangle, the area is also a whole number. Such a triangle is a Heronian triangle. Much of the activity focuses on Heronian triangles.

Two types of Heronian triangles are emphasized. The one type is almost equilateral. The other type has one side that is 3 units long.