1. Honors Geometry Proofs Involving Angles

2. Here are some suggestions that may help you when doing proofs.

3. 1. Your given information (hypothesis) becomes your first statement. What you need to prove (conclusion) is your last statement.

4. 2. Reason backwards when possible.

5. 3. Consider each piece of given information separately and make any conclusion that follows.

6. 4. In most proofs, you will have to write out at least one statement based on the figure. You may look for ONLY the following: a)Angle Addition postulate b)Segment Addition Postulate c)Linear pairs d)Vertical Angles

7. 5. In most proofs, you will use the Substitution Property shortly after the statement you make based on the figure (usually within two steps). Watch for it!

8. Right Angle Theorem (RAT) If _______________________ then_____________________ All right angles are congruent. two angles are right angles the angles are congruent.

9. Given: _______________ Prove:_______________ 1. 1. 2. 2. 3. 3. AB Given Def. of right angles Substitution

10. Congruent Supplements Theorem If two angles are supplements of the same or congruent angles, then they are congruent.

12. Vertical angles are the nonadjacent angles formed when two lines intersect. Vertical Angle Theorem (VAT): 1 2 3 4 Vertical angles are congruent.

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