Angle Sum Theorem (Triangle interior and exterior)

Front

What is the Angle Sum Theorem for triangles?

Back

The Angle 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 60 degrees and another is 70 degrees, what is the measure of the third angle?

Back

The third angle is 50 degrees (180 - 60 - 70 = 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 angle A is 40 degrees and angle B is 60 degrees, what is the measure of the exterior angle at vertex C?

Back

The exterior angle at vertex C is 100 degrees (40 + 60 = 100).

Front

What is the relationship between interior and exterior angles in a triangle?

Back

Each exterior angle of a triangle is equal to the sum of the two non-adjacent interior angles.

Front

How do you find the measure of an unknown angle in a triangle?

Back

To find an unknown angle, subtract the sum of the known angles from 180 degrees.

Front

What is the measure of the angles in an equilateral triangle?

Back

In an equilateral triangle, each angle measures 60 degrees.

Front

If a triangle has angles measuring 30 degrees and 70 degrees, what is the measure of the third angle?

Back

The third angle measures 80 degrees (180 - 30 - 70 = 80).

Front

What is the sum of the interior angles of a triangle?

Back

The sum of the interior angles of a triangle is always 180 degrees.

Front

If angle A is 45 degrees and angle B is 45 degrees, what is angle C in an isosceles triangle?

Back

Angle C is 90 degrees (180 - 45 - 45 = 90).