2.6 Proving Angles Congruent• A theorem - a conjecture or statement that you

prove true.

• Theorem 2.1 – Vertical Angles Theorem– Vertical angles are congruent.

1 3

2 4

Using the Vertical Angles Theorem

• What is the value of x?

2x + 21 = 4x21 = 2x10.5 = x

Congruent Supplements Theorem• If two angles are supplements of the same angle (or of

congruent angles), then the two angles are congruent.

• If and are supplements and and are supplements, then1 3

2 31 2

Theorems• Theorem 2.3 – Congruent Complements Theorem– If two angles are complements of the same angle (or of

congruent angles), then the two angles are congruent.

• Theorem 2.4 – All right angles are congruent.

• Theorem 2.5 – If two angles are congruent and supplementary, then each is a right angle.

More Practice!!!!!

• Classwork – p. 124 – 127 #6 – 12, 16, 17, 20 – 22, 26 – 29, 33 – 35 ALL.

• Homework – Finish classwork.