Warm Up 08.25.11Week 2

Circle the congruent segments and congruent angles:

2) 1)

Homework4) ( 1, 3 )

5) ( 5, -7 )

6) ( 3.5, 2 )

17) ( -4, 3 )

18) ( 1, 2 )

19) ( 4, 6.5 )

20) ( -5, .5 )

21) ( -3, 3 )

22) ( 4 , -7 )

23) ( -0.625 , 3.5 )

24) ( -3 , 1.5 )

Geometry1.5 Day 2

I will bisect an angle and find the measure of an angle using

algebra

Segment Bisector

A segment, line, ray, or plane that intersects a segment at the midpoint.

Ex 1

•A BM

C

D

•

•Bisector

Midpoint

Ex 2

Angle Bisector

A ray that divides an angle in half and creates adjacent angles that are congruent

A

B

C

•

•

•D CD Bisects ACB∠

m ACD = ∠ m DCB∠

Ex 3

Q

R

S• •

•P

QR Bisects PQS∠

m PQR = ∠ m PQS ∠

55º

Find missing Angles

55º = m PQS ∠

2

2

55º = m PQS ∠(2)

110º = m PQS ∠

m PQR = ∠ m RQS ∠

55º = m RQS ∠

Ex 4

S •

Q

R

••

P

m∡PQR = 70º

Find Angle

Bisector

QS bisects ∡PQR

70º2

= 35º

Ex 5

O

RQ •

•

•P

OQ Bisects POR∠

Using Algebra

m∡POQ = m∡QOR

( 2x+ 5 )

( 5x – 46 )

5x – 46 = 2x + 5

5x - 2x - 46 = 5

3x – 46 = 5

3x = 5 + 46

3x = 51

x = 17

x = 17Using Algebra

m∡POQ = 5x – 46 m∡QOR = 2x + 5

= 5( 17 ) – 46

= 85 – 46

= 39ºm∡POQ

= 2( 17 ) + 5

= 34 + 5

= 39ºm∡QOR

Review

Assignment

Textbook page 39, 34 – 54 all except # 43

What is an angle bisector?

DO 1:

OR

Q

•••

P ( 7x - 8 )( 3x + 16 )

What is the m∡POQ?

OQ Bisects POR∠