Indirect Proof

Front

What is an indirect proof?

Back

A proof that involves indirect reasoning, also known as proof by contradiction.

Front

What is the first step of an indirect proof?

Back

Assume the negation of what you are trying to prove.

Front

In an indirect proof, what must be shown to be false?

Back

The temporary assumption made at the beginning of the proof.

Front

What assumption would you make to start the indirect proof of: there can be only one 90 angle in a triangle?

Back

Assume there can be more than one 90 angle in a triangle.

Front

What assumption would you make to start the indirect proof of ∆ABC≅∆DEF?

Back

Assume ∆ABC≇∆DEF.

Front

What is the purpose of assuming the negation in an indirect proof?

Back

To reach a contradiction that proves the original statement true.

Tags

CCSS.HSG.C.A.3

Front

What is a contradiction in the context of indirect proof?

Back

A statement that is logically inconsistent with the assumptions made.

Front

How does indirect proof differ from direct proof?

Back

Indirect proof assumes the opposite of what is to be proven, while direct proof shows the statement is true through logical steps.

Front

What is the conclusion of an indirect proof?

Back

The original statement is proven true because the assumption led to a contradiction.

Tags

CCSS.8.G.A.5

Front

Can indirect proof be used in geometry?

Back

Yes, it is often used to prove properties of shapes and angles.