Bell Ringer – Put in your notebook. Constructions - Turn to p. 30 ‘Bisect a Segment” Do Steps 1-3 Use half of a sheet of paper in your notes Turn in all packets, compass constructions (bisect a segment) progress reports and missing assignment

Then/Now You measured line segments. Measure and classify angles. Identify and use congruent angles and the bisector of an angle.

Vocabulary ray opposite rays angle side vertex interior exterior degree right angle acute angle obtuse angle angle bisector

A ray is a part of a line it has one endpoint. The symbol for ray is an arrow in one direction → above the name of the ray. An angle is formed by 2 noncollinear rays that have a common endpoint. The rays are the sides of the angles.This common endpoint is called the vertex. Naming an angle When naming an angle use 3 letters, the vertex must be the second letter. You can also name an angle using a number or a single letter.

Example 1 Angles and Their Parts A. Name all angles that have B as a vertex. Answer:

Example 1 Angles and Their Parts Answer: B. Name the sides of  5.

Example 1 Angles and Their Parts C.

Example 1a A. B. C. D.

Example 1b B. A. B. C. D.none of these

Example 1c C. What are other ways to name for  3?  AXB,  BXA,  NXA,  AXN Could we also name  3 as  X?

Concept

Example 2 Measure and Classify Angles A. Measure  TYV and classify it as right, acute, or obtuse. Answer: m  TYV = 90, so  TYV is a right angle.

Example 2 Measure and Classify Angles Answer: 180 > m  WYT > 90, so  WYT is an obtuse angle.

Example 2 Measure and Classify Angles

Example 2a A.30°, acute B.30°, obtuse C.150°, acute D.150°, obtuse A. Measure  CZD and classify it as right, acute, or obtuse.

Example 3 Measure and Classify Angles INTERIOR DESIGN Wall stickers of standard shapes are often used to provide a stimulating environment for a young child’s room. A five-pointed star sticker is shown with vertices labeled. Find m  GBH and m  HCI if  GBH   HCI, m  GBH = 2x + 5, and m  HCI = 3x – 10.

Example 3 Measure and Classify Angles  GBH   HCIGiven m  GBH= m  HCIDefinition of congruent angles 2x + 5= 3x – 10Substitution 2x + 15= 3xAdd 10 to each side. 15= xSubtract 2x from each side. Step 1 Solve for x.

Example 3 Measure and Classify Angles Step 2 Use the value of x to find the measure of either angle.. Answer: m  GBH = 35, m  HCI = 35

Example 3 A.m  BHC = 105, m  DJE = 105 B.m  BHC = 35, m  DJE = 35 C.m  BHC = 35, m  DJE = 105 D.m  BHC = 105, m  DJE = 35 Find m  BHC and m  DJE if  BHC   DJE, m  BHC = 4x + 5, and m  DJE = 3x + 30.

Exit Ticket p Class Assignment and HW p , 9-10, 32, 47, 51, 54, 56, 65, Copy an angle using a compass and protractor