Triangle Sum Theorem and Exterior Angle Theorem

Front

What does the Triangle Sum Theorem state?

Back

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

Front

What are the measures of the interior angles of a triangle if they are represented as 9x + 4, 97, and 4x + 1?

Back

The measures of the triangle are 97°, 58°, and 25°.

Front

If the interior angles of a triangle are 5y + 3, 34, and 4y + 8, what are the measures of the angles?

Back

The measures of the triangle are 34°, 68°, and 78°.

Front

What is the value of y if the remote interior angles of a triangle are 4y - 4 and 3y, and the exterior angle is 52°?

Back

y = 8.

Front

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

Back

180°.

Front

Define an exterior angle of a triangle.

Back

An exterior angle of a triangle is formed by one side of the triangle and the extension of an adjacent side.

Front

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

Back

The exterior angle is equal to the sum of the measures of the two remote interior angles.

Front

If one angle of a triangle is 90°, what can you say about the other two angles?

Back

The other two angles must sum to 90° because the total must equal 180°.

Front

What is the measure of an exterior angle if the remote interior angles are 30° and 50°?

Back

The exterior angle measures 80° (30° + 50°).

Front

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

Back

Subtract the sum of the known angles from 180°.