5-5 Indirect Proof and Inequalities in One Triangle - GEOMETRY

The video tutorial covers indirect proof, explaining how to prove a statement by disproving its opposite. It details the steps involved in indirect proof using the example of proving no obtuse angles exist in a right triangle. The tutorial also discusses the relationship between angles and sides in a triangle, emphasizing that the largest angle is opposite the largest side. Finally, it explains the triangle inequality theorem, which states that the sum of the lengths of any two sides of a triangle must be greater than the length of the third side.

What is the first step in writing an indirect proof?

Explain the process of assuming the opposite of a conjecture in an indirect proof.

How do you demonstrate that an assumption leads to a contradiction in an indirect proof?

Describe how to determine the longest side of a triangle based on its angles.

What must be true about the sum of the two smaller sides of a triangle?

How can you prove that two sides cannot form a triangle?

What is the triangle inequality theorem?