s ection 1.2 p oolroom m ath. a n a ngle an angle is formed by joining two rays together at a common...
TRANSCRIPT
AN ANGLE
An angle is formed by joining two rays together at a common endpoint.
Draw a ray on your paper. Label it ray AB. Draw a second ray on your paper so endpoint
from AB is shared by this new ray. Label the new ray AC.
The rays that make up the angle are called sides.
The common endpoint is called the vertex.
sides
sides
vertex
SOME ANGLES ARE SLIGHTLY HARDER TO NAME
A 1 has been placed in an angle. Name this angle using three letters.
RUV
VUR
But not U
When you draw an angle you actually draw two different angles: The angle and its reflex angle.
AngleReflex Angle
Measures between 0o and 180o
Measures between 180o and 360o
Place the center mark of the protractor at the vertex.
Line up the zero mark of the protractor with a side of the angle.
Read the measure of the angle using the other ray.
Be sure to read the correct scale. Was your angle acute or obtuse?
Smartboard File
A ray is an angle bisector if it divides an angle into two congruent angles.
divides angle ABC into two congruent angles.
CDuuur
ACD BCD
Look for the angle bisectors and congruent angles in the figures below.
1.Name each angle bisector and the angle it bisects.2.Name all the congruent angles in the figure. Use the congruence symbol and name the angles so there is no confusion about which angle you mean.
VIRTUAL POOL
When a ball hits the cushion of a pool table the incoming angle is formed. two angles are formed.
When the ball leaves the cushion a second angle is formed called the outgoing angle.
The incoming angle equals the outgoing angle.
1) Use your protractor to measure angle 1. Which is the correct outgoing angle? Which point A or B will the ball hit?
2) Which point on the cushion – W, X, or Y – should the white ball hit so that the ray of the outgoing angle passes through the center of the 8-ball?
4) How would you hit the white ball against the cushion so that the ball passes over the same spot on the way back?