4.07 Proving Angle Relationships

Introduction

Are you feeling a little confused about proofs? Here are a few tips that might help you out.

• The proof always starts with the given information, so "given" is always the first reason.
• If you are trying to decide on which reason is correct for a statement, ask yourself, "How do I know that this statement is true based on the previous statements?"
• The given information can provide hints as to what reasons you might use. If you see the word "midpoint", you might need to use the Midpoint Theorem. If you see the word "bisects", you might need to use the definition of a bisector.
• If a statement is an equation that has only changed slightly from the previous statement, then a good guess for the reason would be the Substitution Property. Check to see if something has been replaced by something that has an equal value.

Go to 4.07 Confused Discussion and tell something that you have been confused about in the previous lessons on proofs. It might be a specific proof that you didn't understand or maybe just a definition, theorem, postulate, or property that you are confused about. It could also be that you don't understand that difference between two things, such as the definition of midpoint and the Midpoint Theorem. Then, reply to someone's post and try to help them understand what they posted about.