MM Triangle Theorems

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 measures 90°, what type of triangle is it?

Back

It is a right triangle.

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

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

Back

Subtract the sum of the two known angles from 180°.

Front

What is an isosceles triangle?

Back

An isosceles triangle is a triangle that has at least two sides of equal length.

Front

What is an equilateral triangle?

Back

An equilateral triangle is a triangle in which all three sides are of equal length and all three angles are equal to 60°.

Front

What is a scalene triangle?

Back

A scalene triangle is a triangle in which all three sides are of different lengths.

Front

If two angles of a triangle are equal, what can be said about the sides opposite those angles?

Back

The sides opposite the equal angles are also equal in length.

Front

What is the range of possible lengths for the third side of a triangle with sides measuring 4 mm and 7 mm?

Back

The length of the third side must be more than 3 mm but less than 11 mm.

Front

What is the relationship between the angles and sides in a triangle?

Back

In a triangle, larger angles are opposite longer sides.