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 endpointRays are called the sides of the angleCommon endpoint is called the vertexNamed 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

vertex

side

side

ABC

B

A

C

Measure of an angle

You use a protractor to measure an angle – different kinds different ways to do itAngle measure is in degreesAngle is always the shortest rotation between the two sides about the vertexReflex 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 anglesThese 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 problemAnswer the questions and work as a group

Widgets

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

Counterexample

Find something that fits your definition but isn’t really what you are trying to findThis is what I will do on purpose when you are talking about a process or ideas to get a better definition from youA 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 definitionsRight Angle

angle measure exactly 90 degreesAcute Angle

angle measure is between 0 and 90Obtuse Angle

angle measure is between 90 and 180

Con’t

Complementary Angles2 angles that add to 90

Supplementary Angles2 angles that add to 180

Vertical Anglesangles formed when two lines intersect, they are

across from each other and are congruentLinear Pairs

2 angles that are adjacent and are supplementaryAdjacent – two angles that share a side and vertex

Homework

Pg 42 1,7-10, 16 and 17Pg 52 15-24