Triangle Inequality Theorem (Ordering and Forming Triangles)

Front

What is the Triangle Inequality Theorem?

Back

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

Front

Which set of side lengths will NOT form a triangle?

Back

3, 6, 12 and 7, 7, 14 will NOT form a triangle because they do not satisfy the Triangle Inequality Theorem.

Front

If side lengths are 10 inches and 17 inches, what could be the length of the third side?

Back

The length of the third side must be between 7 inches and 27 inches (10 + 17 > AC > 17 - 10). Thus, 16 inches is a valid length.

Front

List the side measures in order from shortest to longest: 5, 12, 9.

Back

5, 9, 12.

Front

How do you determine the longest side of a triangle?

Back

The longest side of a triangle is opposite the largest angle.

Front

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

Back

In a triangle, the larger the angle, the longer the side opposite that angle.

Front

If two sides of a triangle are equal, what type of triangle is it?

Back

It is an isosceles triangle.

Front

What is the minimum length of a side in a triangle if the other two sides are 8 and 10?

Back

The minimum length must be greater than 2 (10 - 8).

Front

What is the maximum length of a side in a triangle if the other two sides are 5 and 7?

Back

The maximum length must be less than 12 (5 + 7).

Front

Identify the smallest angle in a triangle with sides 5, 12, and 13.

Back

The smallest angle is opposite the shortest side, which is 5.