Understanding Angles
What is the name of an angle that measures less than 90 degrees?
Acute Angle
What is the measure of a right angle in degrees?
90 Degrees
What tool do you use to measure angles?
Protractor
When a transversal crosses two parallel lines, what name is given to pairs of angles that are equal and sit in matching corners?
Corresponding Angles
Name the angle formed when two lines meet and create a straight line. What is its measure in degrees?
Straight Angle; 180 Degrees
If an angle is one-half of a right angle, what is its measure in degrees and what is that angle type called?
45 Degrees; Acute
When using a protractor, which point must be placed at the vertex of the angle?
Center Hole (Vertex)
If two parallel lines are cut by a transversal, what is the relationship between corresponding angles?
They are congruent (equal).
If an angle measures 65 degrees, is it acute, right, obtuse, or straight? Explain.
Acute, 65 degrees is less than 90 degrees.
If an angle is one-half of a right angle, what is its measure in degrees and what is that angle type called?
45 Degrees; Acute Angle
A student measures an angle using the inner scale on a protractor and reads 40 degrees. If the outer scale reading at the same mark is 140 degrees, which reading is correct for an acute angle? Explain.
40 degrees is correct for an acute angle because it is less than 90 degrees.
Two parallel lines are cut by a transversal. One interior angle on the same side of the transversal measures 110 degrees.
1. What is the measure of the interior adjacent angle on the same side?
2. Are these two angles supplementary or complementary?
1. 70 Degrees; 180 - 110 = 70.
2. Supplementary
Two angles share a vertex and a side but do not overlap. What are these angles called?
Adjacent Angles
An angle measures 135 Degrees. Using benchmark angles, explain whether this angle is closer to a right angle or a straight angle and by how many degrees.
It is in the middle, as it is 45 degrees from each.
Measure and find the missing angle: Two rays form an angle and one ray is extended to make a straight line. If the smaller angle is 25 degrees, what is the measure of the angle adjacent to it on the straight line?
The adjacent angle is 155 degrees because 180−25=155 degrees
When a transversal intersects two parallel lines, alternate interior angles are formed. If one alternate interior angle measures 47 degrees, what is the measure of its alternate interior partner?
47 Degrees
Draw an angle labeled ∠ABC. Make sure you label it!
Two angles add up to a straight angle. If one angle is 110 degrees, what is the other angle? Name the relationship between these two angles.
70 Degrees; Supplementary
On a protractor, an angle's ray lines up at the 0 degrees mark and the other ray lines up at the 150 degree mark. What is the measure of the angle? Show the subtraction step you would use.
The angle measure is 150 degrees; 150 - 0 = 150 degrees
Two parallel lines are cut by a transversal. One angle is an exterior angle measuring 47 degrees. What is the measure of the interior angle on the same side of the transversal, and why?
133 Degrees; 180 - 47 = 133