Interior Angles of 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°.

Front

If one angle of a triangle is 90°, what type of triangle is it?

Back

It is a right triangle.

Front

What is an acute angle?

Back

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

Front

What is an obtuse angle?

Back

An obtuse angle is an angle that measures more than 90° but less than 180°.

Front

How do you find the missing angle in a triangle?

Back

Subtract the sum of the known angles from 180°.

Front

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

Back

The third angle measures 90°.

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

What is a scalene triangle?

Back

A scalene triangle is a triangle with all sides and angles of different measures.

Front

If one angle of a triangle is 60° and another is 80°, what is the measure of the third angle?

Back

The third angle measures 40°.

Front

What is the formula to calculate the missing angle in a triangle?

Back

Missing angle = 180° - (Angle 1 + Angle 2).