Radian measure and arc length
Convert between degrees and radians; calculate arc length and sector area using radians
What you'll learn
- 1
A radian is a way of measuring angles using the radius of a circle. Imagine wrapping the radius around the edge of the circle — that arc length is 1 radian.
- 2
What is 1 radian equal to?
- 3
Drag the angle to show 1 radian on this circle. The arc length should equal the radius.
- 4
Let's find the arc length when the radius is 5 cm and the angle is 2 radians.
- 5
What is the arc length if radius = 3 cm and angle = 4 radians?
- 6
Set the radius to 6 cm and the angle to 1.5 radians. What is the arc length?
- 7
An arc length of 8 cm with a radius of 2 cm means the angle is how many radians?
Practise Radian measure and arc length with Whizlo
Free AI-tutored lessons, unlimited practice questions, and progress tracking for ages 16–18. Aligned to the UK National Curriculum.