Triangle Sum Theorem & Exterior Triangle Theorem

Front

What does the Triangle Sum Theorem state?

Back

The Triangle Sum Theorem states that the sum of the interior angles of a triangle is always 180 degrees.

Front

If one angle of a triangle is 70 degrees and another is 60 degrees, what is the measure of the third angle?

Back

The third angle measures 50 degrees (180 - 70 - 60 = 50).

Front

What is the Exterior Angle Theorem?

Back

The Exterior Angle Theorem states that the measure of an exterior angle of a triangle is equal to the sum of the measures of the two opposite interior angles.

Front

If one exterior angle of a triangle is 120 degrees, and one of the opposite interior angles is 50 degrees, what is the measure of the other opposite interior angle?

Back

The other opposite interior angle measures 70 degrees (120 - 50 = 70).

Front

What is the relationship between the angles in a right triangle?

Back

In a right triangle, one angle is 90 degrees, and the sum of the other two angles is 90 degrees.

Front

If a triangle has angles measuring 30 degrees and 60 degrees, what is the measure of the third angle?

Back

The third angle measures 90 degrees (180 - 30 - 60 = 90).

Front

How do you find the measure of an angle in a triangle if you know the measures of the other two angles?

Back

You subtract the sum of the known angles from 180 degrees.

Front

What is the sum of the angles in any triangle?

Back

The sum of the angles in any triangle is always 180 degrees.

Front

If a triangle has one angle measuring 40 degrees and the other two angles are equal, what are the measures of the other two angles?

Back

The other two angles each measure 70 degrees (180 - 40 = 140; 140/2 = 70).

Front

What is the measure of an exterior angle if the two opposite interior angles are 45 degrees and 55 degrees?

Back

The exterior angle measures 100 degrees (45 + 55 = 100).