Download 1.3 - Angle Definitions

Good Afternoon!
• We have several things to do today so
please be ready with your completed
homework assignment, textbook, graph
paper and your definitions pages.
–The Glovernment
What’s a widget?
Think-Pair-Share:
Decide which figure(s) (A, B, C, or D) are widgets.
How do you know?
What makes a widget a widget?
What is a square?
• A square is a figure with four equal sides.
• “A square is a 4-sided figure with all sides
congruent and all angles measuring 90
degrees.”
Steps to Creating a Good Definition
• Classify your term. What is it?
• Differentiate your term. How does it differ
from others in it’s class?
“A square is a 4-sided figure with all sides
congruent and all angles measuring 90
degrees.”
Define these terms:
• Parallel Lines
• Perpendicular Lines
PLANE that
Parallel lines are lines in the same _______
INTERSECT
never ___________.
LINES that
Perpendicular lines are ________
___________________________.
INTERSECT AT A RIGHT ANGLE (90°)
With your partner…
• Create quality definitions for all 7 terms on
pages 49 and 50. Be sure you both agree on
the wording of your definition.
• Put them in your yellow definitions pages.
• Use pencil! We will go over them and you
may need to make corrections.
Right Angle
• A right angle is an angle that measures 90
degrees.
Acute Angle
• An acute angle is an angle that measures less
than 90 degrees.
Obtuse Angle
• An obtuse angle is an angle that measures
more than 90 degrees but less than 180
degrees.
Complementary Angles
• Complementary angles are a pair of angles
that have a sum of 90 degrees.
Supplementary Angles
• Supplementary angles are a pair of angles that
have a sum of 180 degrees.
Vertical Angles
• Vertical angles are a pair of angles formed by
two intersecting lines that share a common
vertex but not a common side.
Linear Pair of Angles
• A linear pair of angles are supplementary
angles that share a vertex and a common side
(they’re adjacent).
TRUE or FALSE?
A ray that divides an angle into two
angles is an angle bisector.
FALSE
“Counterexample”
TRUE or FALSE?
If two circles intersect, then they
must intersect at exactly two points.
FALSE
Classwork/Homework
• Group work: True/False Questions 1.3 #15-24
– If the statement is true, just write “True”. There
are only four true statements.
– If the statement is false, write “False” then draw
a counterexample to prove your claim.
– We will go over these before you leave today.
• Homework: 1.3 #1-9, 11