Embedded Files
Learning Targets
I can find unknown angle measures by reasoning about adjacent angles with known measures.
I can recognize when an angle measures 90°, 180°, or 360°.
Notes
Notes
When two lines intersect and form four equal angles, we call each one a right angle. A right angle measures 90°. You can think of a right angle as a quarter turn in one direction or the other.
An angle in which the two sides form a straight line is called a straight angle. A straight angle measures 180°. A straight angle can be made by putting right angles together. You can think of a straight angle as a half turn, so that you are facing in the opposite direction after you are done.
If you put two straight angles together, you get an angle that is 360°. You can think of this angle as turning all the way around so that you are facing the same direction as when you started the turn.
When two angles share a side and a vertex, and they don't overlap, we call them adjacent angles.
* REMEMBER* Mathematicians often use 3 points to refer to an angle to be sure others will understand which angle we’re talking about.
90° Angles
180° Angle
360° Angle
Vocabulary
Vocabulary
adjacent angles
Adjacent angles share a side and a vertex.
In this diagram ABC, angle DBC is adjacent to angle .
right angle
A right angle is half of a straight angle. It measures 90 degrees.
straight angle
A straight angle is an angle that forms a straight line. It measures 180 degrees.
Activities
Activities
1.2 Pattern Block Angles
1.2 Pattern Block Angles
Look at the different pattern blocks inside the applet. Each block contains either 1 or 2 angles with different degree measures. Which blocks have only 1 unique angle? Which have 2?
If you place three copies of the hexagon together so that one vertex from each hexagon touches the same point, as shown, they fit together without any gaps or overlaps. Use this to figure out the degree measure of the angle inside the hexagon pattern block.
Using the applet, figure out the degree measure of all of the other angles inside the pattern blocks. (Hint: turn on the grid to help align the pieces.)
1.3 More Pattern Block Angles
1.3 More Pattern Block Angles
Use pattern blocks in the applet to determine the measure of Angle a, Angle b, and Angle c.
If an angle has a measure of 180° then the two legs form a straight line. An angle that forms a straight line is called a straight angle. Using the applet, find as many different combinations of pattern blocks as you can that make a straight angle (Angle c).
1.4 Measuring Like This or That
1.4 Measuring Like This or That
Tyler and Priya were both measuring angle TUS.
Priya thinks the angle measures 40 degrees. Tyler thinks the angle measures 140 degrees. Do you agree with either of them? Explain your reasoning.
Protractors are often labeled with two sets of angle measures, so we need to consider which side of the protractor we’re measuring from!
STEPS:
Place the midpoint of the protractor on the VERTEX of the angle.
Line up one side of the angle with the zero line of the protractor (where you see the number 0).
Read the degrees where the other side crosses the number scale.
Assignment
Assignment
Check Google Classroom!
Report abuse