10 1 Angles Indicator G 2 Determine properties

10 -1 Angles Indicator: G 2: Determine properties of 2 dimensional figures

• Angle: Two rays with a common end point • Degree: units used to measure the size of an angle (1 degree is 1/360 of a circle) • Degrees are measured using a protractor

T O 4 M What are the rays that make up this angles? OT & OM

S 2 U How can you name this angle? E Vertex in middle and letters from each side Vertex Only Use a Number

Types of Angles Right Angle = 90º Square in corner always means right angle. Straight Angle =180

X Acute Angle 0 < x< 90 Obtuse Angle Y 90 < y < 180

Steps to draw an angle: 1. Draw a Ray 2. Place the center of the protractor on the endpoint and align the ray at 0 on the protractor 3. Count up by 10’s, then by ones until you get the desired measure and make a dot beside the marking 4. Draw a ray from the common endpoint through the point Try it: Make 75º angle and name it <RST

To show the measure of an angle use the following notation: m<RST = 75° Read: the measure of angle RST is 75 degrees Adjacent Angles: Angles that share a common side and endpoint. Adjacent Non-adjacent

D A 30 B 1) 2) 3) 4) 5) C Name an obtuse angle Name an acute angle Name a pair of adjacent angles Name a pair of non-adjacent angles What is the measure of <ABD, <ABC (use correct notation)

Homework • 10 -1 pages from packet– – Not the LAB PAGES…