

Indirect ProofAKA Proof by contradiction Indirect proof is synonymous with proof by contradiction. A keyword signalling that you should consider indirect proof is the word 'not'. Usually, when you are asked to prove that a given statement is NOT true, you can use indirect proof by assuming the statement is true and arriving at a contridiction.The idea behind the indirect method is that if what you assumed creates a contradiction, the opposite of your initial assumption is the truth.
Example of an Indirect ProofProve that BDA is not a straight angle.
See this indirect proof all by itself(opens up new window, makign it easier to see entirity of proof below)
