Int. & Ext. Angles in Triangles

Front

What is an interior angle of a triangle?

Back

An interior angle is formed by two sides of a triangle that meet at a vertex, and the sum of the interior angles in a triangle is always 180 degrees.

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 two opposite interior angles.

Front

How do you calculate the measure of an interior angle if you know the other two angles?

Back

Subtract the sum of the known interior angles from 180 degrees.

Front

What is the relationship between the 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 one interior angle of a triangle is 70 degrees and another is 56 degrees, what is the third angle?

Back

The third angle is 54 degrees (180 - 70 - 56 = 54).

Front

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

Back

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

Front

What does it mean for triangles to be similar?

Back

Triangles are similar if their corresponding angles are equal and their corresponding sides are in proportion.

Front

If two angles of a triangle are 45 degrees and 55 degrees, what type of triangle is it?

Back

It is an acute triangle because all angles are less than 90 degrees.

Front

What is the measure of an exterior angle if the interior angle is 36 degrees?

Back

The exterior angle is 144 degrees (180 - 36 = 144).

Front

How can you determine if two triangles are similar using angle-angle (AA) similarity?

Back

If two angles of one triangle are equal to two angles of another triangle, then the triangles are similar.