How to determine if three lengths make up a triangle

The video tutorial explains how to determine if given side lengths can form a triangle using the triangle inequality theorem. It introduces the concept, explains the theorem, and demonstrates its application with examples. The key idea is that the sum of any two side lengths must be greater than the third side length for the sides to form a triangle.

What is the first step in determining if given side lengths can form a triangle?

• Subtract the smallest side from the largest.

• Ensure the sum of any two sides is greater than the third.

• Check if all sides are equal.

• Add up all the side lengths.

According to the triangle inequality theorem, what must be true for three side lengths to form a triangle?

• All sides must be of different lengths.

• The sum of any two sides must be less than the third side.

• The sum of any two sides must be greater than the third side.

• The sides must form a right angle.

If you have side lengths of 9, 15, and 4, can they form a triangle?

• Yes, because 9 + 15 is greater than 4.

• No, because 9 + 4 is not greater than 15.

• Yes, because 4 + 15 is greater than 9.

• No, because 15 is the largest side.

Which of the following sets of side lengths can form a triangle?

• 3, 4, 8

• 5, 5, 5

• 1, 1, 3

• 2, 2, 5

Why is it unnecessary to check all combinations of side lengths once a 'no' is found?

• Because one 'no' means the sides cannot form a triangle.

• Because the smallest side is always incorrect.

• Because the sides are already equal.

• Because the largest side is always correct.