Triangles and Angles

If you measure and add the angles in any triangle, you will find that the sum of the angles have a special relationship.

Theorem 1: Angle Sum Theorem The sum of the measures of the angles of a triangle is 180 .

Theorem 2: The acute angles of a right triangle are complementary.

Theorem 3: The measure of each angle of an equiangular triangle is 60.

Learn more about the Angle Sum Theorem by reading the explanation below.

Triangles and Angles

Practice: Apply what you learned about the Angle Sum Theorem by answering the following exercises:

Triangles and Angles 1

Triangles and Angles 2

Triangles and Angles 3