Properties 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

What is an equilateral triangle?

Back

An equilateral triangle is a triangle with all three sides of equal length and all three angles measuring 60°.

Front

What is the Triangle Inequality Theorem?

Back

The Triangle Inequality Theorem states that the sum of the lengths of any two sides of a triangle must be greater than the length of the third side.

Front

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

Back

It is a right triangle.

Front

What is an isosceles triangle?

Back

An isosceles triangle is a triangle with at least two sides of equal length and the angles opposite those sides are equal.

Front

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

Back

To find the measure of the third angle, subtract the sum of the two known angles from 180°.

Front

What is a scalene triangle?

Back

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

Front

What is the relationship between the angles in a triangle?

Back

The angles in a triangle are related such that the smallest angle is opposite the shortest side, and the largest angle is opposite the longest side.

Front

What is the measure of each angle in a right triangle?

Back

In a right triangle, one angle measures 90°, and the other two angles must add up to 90°.

Front

What is the exterior angle theorem?

Back

The exterior angle theorem states that the measure of an exterior angle of a triangle is equal to the sum of the measures of the two opposite interior angles.