Introduction to radians | Unit circle definition of trig functions | Trigonometry | Khan Academy

What type of angle measures exactly 90 degrees?

• Acute angle

• Obtuse angle

• Right angle

• Straight angle

How many degrees are in a full rotation around a circle?

• 90 degrees

• 180 degrees

• 270 degrees

• 360 degrees

Besides degrees, what other unit of angle measurement is introduced in the video?

• Gradians

• Steradians

• Radians

• Revolutions

What is the definition of one radian in a circle?

• The angle where the arc length is half the radius.

• The angle where the arc length is equal to the radius.

• The angle where the arc length is twice the radius.

• The angle where the arc length is equal to the diameter.

How many radians are in a full circle (360 degrees)?

• π radians

• 2π radians

• π/2 radians

• 360 radians

How many radians are equal to 180 degrees?

• π radians

• 2π radians

• π/2 radians

• 1 radian

To convert 1 radian to degrees, what expression would you use?

• 180/π degrees

• π/180 degrees

• 360/π degrees

• π/360 degrees