+

Objective: Bisect and angle

DO NOW: p. 60 in textbook (Folding Angle Bisectors)

HOMEWORK:1.2.2 Practice

Worksheet A2.Open notes

vocabulary quiz tomorrow (2.1-2.3)

DATE

Oct. 6, 2014

+Homework Check

1. Yes (tic marks)

2. No (no tic marks)

3. No (its an endpoint)

4. PM = 11; MD = 11

5. TM = 7.5; MS = 7.5

6. AM = 9.2; AB = 18.4

7. FG = 17; EG = 34

8. x = 3

9. x = 5

10. (1, 1)

11. (2.5, -4)

12. (-4, 4)

13. (3.5, -3)

14. (2, 2.5)

15. (-2, 4)

16. 5.5 ft

2.1 B

+IMPORTANT TERMS

Angle bisector: An angle bisector is a ray that divides an angle into two angles that are congruent.

+Example 1

BD bisects LABC, and mLABC = 110o

Find mLABD and mLDBC

Find angle measures

+Solution

BD bisects LABC, so mLABC is half of mLABC.

mLABD

Example 1

+Check Point

HK bisects LGHJ. Find mLGHK and mLKHL.

1. mLGHK =

mLKHL =

2. mLGHK =

mLKHL =

3. mLGHK =

mLKHL =

+Solutions

1. mLGHK = 16o

mLKHL = 16o

2. mLGHK = 45o

mLKHL = 45o

3. mLGHK = 80.5o

mLKHL = 80.5o

Checkpoint

+Example 2Angle Measures and Classification

+SolutionsExample 2

+Checkpoint

4. mLSQP = mLPQR =

5. mLSQP = mLPQR =

6. mLSQP = mLPQR =

+Solutions

4. mLSQP = 29o

mLPQR = 58o

acute

5. mLSQP = 45o

mLPQR = 120o

right

6. mLSQP = 60o

mLPQR = 120o

obtuse

Checkpoint

+Example 3Use Algebra with Angle Measures

+SolutionsExample 3

+Follow up

Substitute your value of x in the original equation to determine whether it is a solution.

? ? ?

+Checkpoint

BD bisects LABC. Find the value of x.

+Solution

7. 43

8. 3

Checkpoint

+Closing

Exit Card: Find the segment length. THEN place a +, check, or – for understanding of today’s lesson!

USE THE MIDPOINT FORMULA:

R(5,6)

P(-3, 0)