Triangle Sum and Exterior Angle Theorem Practice

Front

What is the Triangle Sum Theorem?

Back

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

Front

What is the measure of angle b if angle a is 90° and angle c is 54°?

Back

Angle b = 180° - (90° + 54°) = 36°.

Front

If one angle of a triangle is 70° and another is 41°, what is the measure of the third angle?

Back

Third angle = 180° - (70° + 41°) = 69°.

Front

What is an exterior angle of a triangle?

Back

An exterior angle is formed by one side of a triangle and the extension of an adjacent side. The measure of an exterior angle is equal to the sum of the measures of the two opposite interior angles.

Front

If angle x is an exterior angle measuring 94°, what are the measures of the two opposite interior angles?

Back

The sum of the two opposite interior angles = 94°.

Front

What is the relationship between an exterior angle and the interior angles of a triangle?

Back

The exterior angle is equal to the sum of the two non-adjacent interior angles.

Front

If angle A = 51° and angle B = 37°, what is angle C in triangle ABC?

Back

Angle C = 180° - (51° + 37°) = 92°.

Front

What is the measure of an angle if the other two angles in a triangle are 66° and 138°?

Back

The measure of the angle = 180° - (66° + 138°) = -24° (not possible, so the angles do not form a triangle).

Front

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

Back

Subtract the sum of the known angles from 180°.

Front

What is the sum of the angles in a triangle?

Back

The sum of the angles in a triangle is always 180°.