A second type of proof in geometry is a proof by ____________________, or indirect proof.?

Question

A second type of proof in geometry is a proof by ____________________, or indirect proof.

Answer 1

contradiction

Indirect proofs: In an indirect proof, the first statement is the negation of the statement to be proved. An indirect proof of the statement begins with the assumption that the statement is false, i.e., assume that is true. The goal is to show that this assumption leads to a contradiction. At each step, the question is asked, ``What do I need to know in order for the goal to be true?". The answer supplies intermediate goals. The proof terminates when all goals end in a contradiction. Indirect proof is also known as proof by contradiction, top-down proof, goal directed proof, and backward-chaining.

Answer 2

If points A B C were collinear then AB + BC would equal AC because of the addition of segments postulate. So, AB + BC doesn't equal AC.

Answer 3

contradiction

Answer 4

theorem

Answer 5

direct?