290 likes | 421 Views
Lesson 4.4 Angle Properties pp. 135-141. Objectives: 1. To identify linear pairs and vertical, complementary, and supplementary angles. 2. To prove theorems on related angles. D. A. B. C. Definition.
E N D
Lesson 4.4 Angle Properties pp. 135-141
Objectives: 1. To identify linear pairs and vertical, complementary, and supplementary angles. 2. To prove theorems on related angles.
D A B C Definition A linear pair is a pair of adjacent angles whose noncommon sides form a straight angle (are opposite rays).
Definition Vertical angles are angles adjacent to the same angle and forming linear pairs with it. E A B C D
Definition Two angles are complementary if the sum of their measures is 90°. Two angles are supplementary if the sum of their measures is 180°.
C Y 67° 23° T F X CFY and YFX are complementary
C Y 157° 23° T F X TFY and YFX are supplementary
Theorem 4.1 All right angles are congruent.
STATEMENTSREASONS A and B are Given right angles 12. mA = 90° 12. _______________ mB = 90° 13. mA = mB 13. _______________ 14. A B 14. _______________ Def. of rt. angle Substitution Def. of angles
Theorem 4.2 If two angles are adjacent and supplementary, then they form a linear pair.
Theorem 4.3 Angles that form a linear pair are supplementary.
Theorem 4.4 If one angle of a linear pair is a right angle, then the other angle is also a right angle.
Theorem 4.5 Vertical Angle Theorem. Vertical angles are congruent.
Theorem 4.6 Congruent supplementary angles are right angles.
Theorem 4.7 Angle Bisector Theorem. If AB bisects CAD, then mCAB = ½mCAD.
Practice: If the mA = 58°, find the measure of the supplement of A.
Practice: If the mA = 58°, find the measure of the complement of A.
Practice: If the mA = 58°, find the measure of an angle that makes a vertical angle with A.
Practice: If the mA = 58°, find the measure of an angle that makes a linear pair with A.
Practice: If the mA = 58°, find the measures of the angles formed when A is bisected.
Homework pp. 137-141
A F G E B D C ►A. Exercises mAGF = 40°; mBGC = 50°; mAGE = 90°; mEGD = 90°. 7. Name two pairs of supplementary angles.
A F G E B D C ►A. Exercises mAGF = 40°; mBGC = 50°; mAGE = 90°; mEGD = 90°. 9. What is mFGE?
►B. Exercises Give the reason for each step in the proofs below. 18-22. Theorem 4.3 Angles that form a linear pair are supplementary. Given:PAB and BAQ form a linear pair Prove: PAD and BAQ are supplementary
■ Cumulative Review Review properties of equality and inequality (Sections 3.1, 4.1). What would each property of inequality below be? 41. Addition property of
■ Cumulative Review Review properties of equality and inequality (Sections 3.1, 4.1). What would each property of inequality below be? 42. Multiplication property of
■ Cumulative Review Review properties of equality and inequality (Sections 3.1, 4.1). What would each property of inequality below be? 43. Reflexive property of
■ Cumulative Review Review properties of equality and inequality (Sections 3.1, 4.1). What would each property of inequality below be? 44. Transitive property of
■ Cumulative Review Review properties of equality and inequality (Sections 3.1, 4.1). What would each property of inequality below be? 45. Why is not an equivalence relation?