Poolroom Math and Widgets Section 1.2 and 1.3

Angles What is an angle? What makes an angle? Formed by 2 rays with a common endpoint Rays are called the sides of the angle Common endpoint is called the vertex Named by using 3 points on the angle, one point on each side and the vertex, the point that represents the vertex always has to be in the middle or written second

Angle

Measure of an angle You use a protractor to measure an angle – different kinds different ways to do it Angle measure is in degrees Angle is always the shortest rotation between the two sides about the vertex Reflex measure is the largest rotation or the angle subtracted from 360

Using a compass 2 different kinds in your boxes and some may still have others

More Terms Congruent Angles – have the same angle measure, congruency markings Angle Bisector – cuts an angle in half to have 2 congruent angles These terms will be used a lot throughout the year

Virtual Pool Incoming Angle is the angle formed with the path of the ball and the cushion (smaller of the two angles) Outgoing Angle is the angle formed by the cushion and the path of the ball leaving ( smaller angle) Key idea here is the incoming angle and the outgoing angle are congruent

Investigation In your groups work on the Virtual Pool Math problem Answer the questions and work as a group

Widgets Writing a good definition What you are talking about / classify it / how it differs from others(define it) Ex A protractor is a geometric tool used to measure angles A square is ________ that ________

Counterexample Find something that fits your definition but isn’t really what you are trying to find This is what I will do on purpose when you are talking about a process or ideas to get a better definition from you A square is a figure with 4 congruent sides. Draw a figure that fits this but is not a square

Investigation Defining Angles pg 49 Work through this investigation and as a group come up with definitions Right Angle angle measure exactly 90 degrees Acute Angle angle measure is between 0 and 90 Obtuse Angle angle measure is between 90 and 180

Con’t Complementary Angles 2 angles that add to 90 Supplementary Angles 2 angles that add to 180 Vertical Angles angles formed when two lines intersect, they are across from each other and are congruent Linear Pairs 2 angles that are adjacent and are supplementary Adjacent – two angles that share a side and vertex

Homework Pg 421,7-10, 16 and 17 Pg