Angles in Triangles

Front

What is the sum of the interior angles in a triangle?

Back

The sum of the interior angles in a triangle is always 180°.

Front

If one angle in 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 measure of a missing angle in a triangle?

Back

Subtract the sum of the known angles from 180°.

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 the exterior angle theorem?

Back

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

Front

If two angles in a triangle are 40° and 60°, what is the measure of the third angle?

Back

The third angle measures 80° (180° - 40° - 60°).

Front

What is a scalene triangle?

Back

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

Front

What is the formula for the area of a triangle?

Back

The area of a triangle is given by the formula: Area = 1/2 * base * height.