Download Unit 4 Angles

UNIT 4
Angles
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Identifying angles (Page 126-129)
Measuring Angles (Page 130-138)
Drawing Angles (Page 139-142)
Supplementary and Complementary Angles (Page
146-149)
 Missing Angles in Triangles and Quadrilaterals (Page
150-153)
Identifying angles (Page 126-129)
 https://www.youtube.com/watch?v=NVuMULQjb3o
 https://www.youtube.com/watch?v=UgfSwlqi4Qg
 https://www.youtube.com/watch?v=_n3KZR1DSEo
 There are 5 types of angles.
 Right Angle
 Straight Angle
 Acute Angle
 Obtuse Angle
 Reflex Angle
Angles are measured in something called degrees. You measure from
one ray/arm to another. You use a protractor to measure the degrees
in an angle.
Parts of an Angle
Parts of an Angle
Identifying angles (Page 126-129)
 Right angles always equal EXACTLY 90 degrees. Usually
identified by a square on the vertex.
 Straight angles always equal EXACTLY 180 degrees.
 Obtuse angles (I like to think obese to help me
remember,) are bigger than 90 degrees but less than 180
degrees.
 Acute angles (I like to think awe cute cause they’re little,)
are less than 90 degrees but bigger than 0 degrees.
 Reflex angles are bigger that 180 degrees (the opposite
side of all right, acute and obtuse angles are reflex
Practice
Identifying angles: Example PAT question
Assignment
 Textbook Pages 127-128, questions 1-5
Measuring Angles (Page 130-138)
 https://www.youtube.com/watch?v=KtAYV2FqdBE
 https://www.youtube.com/watch?v=R4giTrUEF2k
 https://www.youtube.com/watch?v=t4xCOUNEInI
 You use a protractor to measure the degrees in an
angle.
 Protractors are easy to use once you get the hang of
it.
Measuring Angles (Page 130-138)
Step 1: Decide whether your angle is acute, obtuse, straight, right,
or reflex
Step 2: Line the vertex of the angle on the center circle/cross
section of you protractor
Step 3: Pick an ray/arm to be your base line, line your base line
with the zero line on the protractor
Step 4: Follow the other ray/arm to see where it measures on the
protractor, but be careful there will be two numbers and you
need pick the correct one by remembering what type of angle you
labeled in step 1. If you decided it was an acute angle then the
measurement needs to be less than 90 degrees.
Protractor
Assignment
 Textbook page 132, questions 2 and 3
 Textbook page 136, questions 1- 7
Drawing Angles (Page 139-142)
 https://www.youtube.com/watch?v=6oiDPXle97c
 You’ll need a pencil, a protractor, and a ruler
Step one: Draw a base line
Step 2: Draw a vertex
Step 3: Place your protractor on your vertex and base line
Step 4: Put a dot on the measurement you are drawing. (Remember
what type of angle is it? Acute, obtuse, right, straight?)
Step 5: Connect your dot with the vertex
Step 6: Double check your work
Drawing Angles (Page 139-142)
 What happens when a question asks you to measure or draw a
reflex angle?
 It’s easier then you think. If an angle was to rotate a full circle
that would equal 360 degrees.
 If you were asked to draw a 200 degree angle, that’s 200 degrees
of 360.
 So you go 360-200= 160
 Draw the obtuse angle of 160 and then the exterior angle of that
is the reflex angle 200 degrees.
 Let me show you on the board.
Assignment
 Textbook page 141-142, questions 1-7
Supplementary and Complementary
Angles (Page 146-149)
 https://www.youtube.com/watch?v=DGKwdHMiqCg
 https://www.youtube.com/watch?v=_7FwqgcCSA0
 Complimentary Angles: The easiest what to think of this is a right
angle that has been split in two. Complimentary angles always
total 90 degrees.
 Supplementary Angles: The easiest way to think of this is a
straight angle that has been split in two. Supplementary angles
always total 180 degrees.
Complimentary Angles
Practice
Supplementary Angles
Practice
Supplementary and Complementary
Angles (Page 146-149)
Example PAT questions
Assignment
Worksheet
Missing Angles in Triangles and
Quadrilaterals (Page 150-153)
 https://www.youtube.com/watch?v=YnDeYhBoCzs
 All angles in a triangle total 180 degrees
 https://www.youtube.com/watch?v=6ApegKO75d0
 All angles in a quadrilateral total 360 degrees
Missing angle in a Triangle
 Step 1: Add the two given angles together
 Step 2: Subtract the answer from step 1 by 180
 Step 3: Your answer in step 2 is your missing angle
 If it’s an isosceles triangle (two sides and angles are exactly the
same, you’ll know because they’ll be labeled with the same
letter, like X and X) and they only give you the one angle that is
different you can subtract that angle from 180 and divide by 2.
 Let’s do a couple examples on the board.
Practice
Practice
Assignment
 Textbook page 148-149, questions 1-9
Missing angle in a Quadrilateral
 Step 1: Add the two given angles together
 Step 2: Subtract the answer from step 1 by 360
 Step 3: Your answer in step 2 is your missing angle
 Sometimes they give you a more complicated question,
like a quadrilateral that also has
complimentary/supplementary angles. Don’t panick, just
break it down. Figure out the
complimentary/supplementary angles and then carry on
with the steps above.
Practice
Missing Angles in Triangles and Quadrilaterals
(Page 150-153)
Example PAT question
Assignment
 Textbook page 152-153, question 2, 3, 5, 6, 7, 8, 9
Games
 http://www.math-play.com/Tic-Tac-Toe-Game-ClassifyingAngles/Tic-Tac-Toe-Game-Classifying-Angles.html
 https://www.studyladder.ca/games/activity/types-ofangles-13177
 http://www.mathplayground.com/measuringangles.html
 http://www.abcya.com/measuring_angles.htm
 http://www.amblesideprimary.com/ambleweb/mentalmat
hs/protractor.html
 http://www.crickweb.co.uk/ks2numeracy-tools.html#angle
 http://www.what2learn.com/home/examgames/maths/ang
les1/
 http://www.softschools.com/math/geometry/quadrilateral
s/quadrilateral_angles/