Find the measure of each numbered angle and
Find the measure of each numbered angle and name theorem that justifies your work. Problem of the Day
Section 2 -8 b Proving Angle Relationships
Objectives Then Now You wrote proofs involving supplementary and complementary angles. Write proofs involving congruent and right angles.
Content Standards Common Core State Standards G. CO. 9 – Prove theorems about lines and angles. Mathematical Practices 3) Construct viable arguments and critique the reasoning of others. 6) Attend to precision.
Properties of Angle Congruence
Theorems
Given: ∠ 9 and ∠ 10 are comp. ∠ 8 and ∠ 9 are comp. m∠ 8 = 41 Prove: m∠ 10 = 41 Example 3
Given: ∠ 1 and ∠ 2 are supp. ∠ 2 and ∠ 3 are supp. m∠ 3 = 78 Example 3 Find: m∠ 1 and m∠ 2 (Name theorems you used to justify your work. )
Vertical Angles Theorem
If ∠ 3 and ∠ 4 are vertical angles, m∠ 3 = 6 x + 2, and m∠ 4 = 8 x – 14, find m∠ 3 and m∠ 4. Justify each step. Example 4
If ∠ 1 and ∠ 2 are vertical angles, m∠ 1 = d – 32, and m∠ 2 = 175 – 2 d, find m∠ 1 and m∠ 2. Justify each step. Example 4
Right Angle Theorems
Homework p. 156 #7, 8 -10, 12, 41 -44
If m∠A = 5 x – 12, m∠B = 2 x + 18, ∠A and ∠C are supplementary, and ∠B and ∠C are supplementary, find m∠C. Problem of the Day
- Slides: 14