Triangle Inequality Theorem

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

Can the side lengths 7 yd, 8 yd, and 9 yd form a triangle?

Back

Yes, because 7 + 8 > 9, 7 + 9 > 8, and 8 + 9 > 7.

Front

How many degrees are in a triangle?

Back

180 degrees.

Front

Can the side lengths 3, 5, and 8 form a triangle?

Back

No, because 3 + 5 is not greater than 8.

Front

Can the side lengths 15 in., 12 in., and 2 in. form a triangle?

Back

No, because 15 + 2 is not greater than 12.

Front

What is the sum of the angles in any triangle?

Back

The sum of the angles in any triangle is always 180 degrees.

Front

If one angle of a triangle is 80° and another is 50°, what is the measure of the third angle?

Back

The third angle is 50° (180° - 80° - 50° = 50°).

Front

What does it mean if two triangles have the same angle measures?

Back

It means that the triangles are similar and can be considered congruent if their corresponding sides are also proportional.

Front

What is an example of a set of side lengths that cannot form a triangle?

Back

The side lengths 1, 2, and 3 cannot form a triangle because 1 + 2 is not greater than 3.

Front

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

Back

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