Section2 4
- 1. Special Pairs of Angles Section 2-4
- 2. Three Kinds of “Special” Pairs 1. Complementary Angles (comp. ∠ ’s) – two angles whose sum is 90 degrees. D 60° 30° E F ∠ D and ∠ F are complementary ∠ F is a complement of ∠ D
- 3. Three Kinds of “Special” Pairs 2. Supplementary Angles (supp. ∠ ’s) – two angles whose sum is 180 degrees. 100° 80° X Z ∠ X and ∠ Z are supplementary ∠ X is a supplement of ∠ Z
- 4. So, what’s the difference between a linear pair and supplementary angles?
- 5. Three Kinds of “Special” Pairs 3. Vertical Angles (vert. ∠ ’s) – two nonadjacent angles formed by two intersecting lines 2 1 3 4 ∠ 1 and ∠ 3 are vertical angles ∠ 2 and ∠ 4 are vertical angles
- 6. And One New Theorem Vertical Angle Theorem (VAT) – Vertical angles are congruent. P• •L ∠ POL ≅ ∠ KOJ O J •K ∠ JOP ≅ ∠ LOK •
- 7. Complete with always, sometimes, or never 1. Vertical angles ____________ have a common vertex. 2. Two right angles are ____________ complementary. 3. Right angles are ____________ vertical angles. 4. Angles 1, 2, and 3 are ____________ complementary. 5. Vertical angles ____________ have a common supplement.