Geo 2.3 Triangle Sum & Exterior Angle Theorems

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 degrees.

Front

If angle A is 45 degrees and angle B is 55 degrees, what is angle C?

Back

Angle C = 180 - (Angle A + Angle B) = 180 - (45 + 55) = 80 degrees.

Front

Define an acute angle.

Back

An acute angle is an angle that measures less than 90 degrees.

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 non-adjacent interior angles.

Front

If angle D is an exterior angle and angles E and F are the non-adjacent interior angles, how do you express angle D?

Back

Angle D = Angle E + Angle F.

Front

Classify the triangle with angles measuring 30 degrees, 60 degrees, and 90 degrees.

Back

This triangle is classified as a right triangle.

Front

What is the measure of the third angle in a triangle if the other two angles are 70 degrees and 40 degrees?

Back

The third angle = 180 - (70 + 40) = 70 degrees.

Front

Define an obtuse angle.

Back

An obtuse angle is an angle that measures more than 90 degrees but less than 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 angle A is 25 degrees and angle B is 85 degrees, what is angle C?

Back

Angle C = 180 - (Angle A + Angle B) = 180 - (25 + 85) = 70 degrees.