Angles in Triangles

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 one angle of a triangle measures 90 degrees, what type of triangle is it?

Back

It is a right triangle.

Front

What do you call an angle that measures less than 90 degrees?

Back

An acute angle.

Front

What do you call an angle that measures more than 90 degrees but less than 180 degrees?

Back

An obtuse angle.

Front

In a triangle, if one angle measures 60 degrees and another measures 80 degrees, what is the measure of the third angle?

Back

The third angle measures 40 degrees.

Front

What is the relationship between the angles in an isosceles triangle?

Back

In an isosceles triangle, the angles opposite the equal sides are equal.

Front

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

Back

Subtract the sum of the known angles from 180 degrees.

Front

What is an equilateral triangle?

Back

An equilateral triangle is a triangle where all three sides and all three angles are equal, each measuring 60 degrees.

Front

If two angles of a triangle are 45 degrees each, what is the measure of the third angle?

Back

The third angle measures 90 degrees.

Front

What is the exterior angle theorem?

Back

The exterior angle of a triangle is equal to the sum of the two opposite interior angles.