Angle Basics
What do we call the figure formed by two rays that share a common endpoint?
An angle
What tool do you use to measure an angle in degrees?
A protractor.
What do we call an angle smaller than 90 degrees?
Acute
True or False: The measure of a straight angle is 180°.
True
How many one-degree angles are in a full circle?
360
If one ray of an angle lines up with 0° on a protractor and the other ray lines up with 60° on the outer scale, what is the measure of the angle?
60°
What do we call an angle larger than 90 degrees but less than 180 degrees?
Obtuse
If one part of an angle measures 60° and the other part measures 30°, what is the whole angle's measure?
90°
Name an angle that measures exactly 90 degrees.
A right angle
Use a protractor to sketch a 25° angle from a given ray.
Teacher checks student drawings!
If two lines intersect and make a 60° angle in one region, what is the measure of the angle vertically opposite it?
60° (vertical angles are equal)
Angles A–H each have the same measurement. If one labeled angle is 45°, what is the measure of all Angles A–H? Explain your reasoning.
45° for each
Is an angle that measures 120 degrees acute, right, or obtuse? Explain.
Obtuse; because 120° is greater than 90° and less than 180°.
Use a protractor to sketch a 60° angle from the same given ray.
Teacher checks student drawings!
The 60° angle, the 30° angle, and Angle A together make a straight angle. Is Angle A acute or obtuse? Explain.
Angle A is NEITHER, it is a right angle since it is 90°.
On a diagram, one angle is 120° and it is split into two non-overlapping angles. If one piece is 75°, what is the other piece? Show the subtraction.
45° (120° − 75° = 45°).
Draw or describe how two line segments can be parallel or perpendicular
Parallel segments never meet; perpendicular segments meet at a right angle.
A protractor shows one ray at 0° and another at 87°. Which answer is correct: 74°, 87°, 93°, or 167°?
87°, it's read from 0° to 87° on outer scale.