Download presentation

Presentation is loading. Please wait.

Published byEmmanuel Jean Modified over 2 years ago

1
**Objectives Students should know 1. How to name and classify angles.**

2. How to use Angle Addition Postulate 3, How to use angle bisector..

2
**Vocabulary Do you know? Angle Vertex Measure Degree**

Interior of an Angle Exterior of an Angle Acute Angle Obtuse Angle Right Angle Straight Angle Congruent Angle Angle Bisector

3
**Name the Angles Name each angle in three or more ways. 1. 2. **

Name three different angles in the figure.

4
Classify the Angles Use the diagram to find the measure of each angle. Then classify each as acute, right, or obtuse. a. BOA b. DOB c. EOC mBOA = 40° BOA is acute. mDOB = 125° DOB is obtuse. mEOC = 105° EOC is obtuse.

5
**Congruent angles are angles that have the same measure.**

Arc marks are used to show that the two angles are congruent. mABC = mDEF, so you can write ABC DEF. This is read as “angle ABC is congruent to angle DEF.”

6
angle bisector An angle bisector is a ray that divides an angle into two congruent angles. JK bisects LJM; thus LJK KJM.

8
**Example 1: Using the Angle Addition Postulate**

mDEG = 115°, and mDEF = 48°. Find mFEG mDEG = mDEF + mFEG Add. Post. Substitute the given values. Subtract 48 from both sides. Simplify.

9
Check it Out: Example 1 mXWZ = 121° and mXWY = 59°. Find mYWZ.

10
**Example 2: Finding the Measure of an Angle**

KM bisects JKL, mJKM = (4x + 6)°, and mMKL = (7x – 12)°. Find mJKM.

11
Example 2 Continued Step 1 Find x. mJKM = mMKL Def. of bisector Substitute the given values. Add 12 to both sides. Simplify. Subtract 4x from both sides. Divide both sides by 3. Simplify.

12
Example 2 Continued Step 2 Find mJKM. Substitute 6 for x. Simplify.

13
Check It Out! Example 2 Find the measure of each angle. JK bisects LJM, mLJK = (-10x + 3)°, and mKJM = (–x + 21)°. Find mLJM. Step 1 Find x. LJK = KJM Def. of bisector (–10x + 3)° = (–x + 21)° Substitute the given values. +x x Add x to both sides. Simplify. –9x + 3 = 21 –3 –3 Subtract 3 from both sides. –9x = 18 Divide both sides by –9. x = –2 Simplify.

14
Check It Out! Example 2 Step 2 Find mLJM. mLJM = mLJK + mKJM = (–10x + 3)° + (–x + 21)° = –10(–2) + 3 – (–2) + 21 Substitute –2 for x. = Simplify. = 46°

15
**Lesson Quiz: Do you understand the lesson?**

Independent Practice Textbook pg 24 #8 and 9 Challenge: pg 25 # 30 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Homework: 1.3 Handout – will be given out once textbook work is checked.

Similar presentations

OK

Holt McDougal Geometry 5-1 Perpendicular and Angle Bisectors 5-1 Perpendicular and Angle Bisectors Holt Geometry Warm Up Warm Up Lesson Presentation Lesson.

Holt McDougal Geometry 5-1 Perpendicular and Angle Bisectors 5-1 Perpendicular and Angle Bisectors Holt Geometry Warm Up Warm Up Lesson Presentation Lesson.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on behaviour of seismic waves Ppt on reduced instruction set computer Ppt on regional transport office chennai Ppt on systematic layout planning Ppt on types of distribution channels Mp ppt online application form Ppt on cross site scripting owasp Ppt on political parties and electoral process in kenya Ppt on rational numbers for class 9 Ppt on water pollution