Problem:
How many non-similar triangles have angles whose degree measures are distinct positive integers in arithmetic progression?
Answer Choices:
A.
B.
C.
D.
E.
Solution:
Let , and be the angles in the triangle. Then
Because the sum of the degree measures of two angles of a triangle is less than , we have
There are triangles with this property.
The problems on this page are the property of the MAA's American Mathematics Competitions