Drag to size

Drag the green handle to create a central angle.

Perfect!

Tap to wrap

A radian is an angle where the arc length exactly equals the radius. Wrap radii around the circle!

Radius
{{ s2_radCount < 4 ? s2_radCount : 'π' }} radians

Half a circle is exactly pi radii!

Slide to convert

Match to its exact radian equivalent.

Degrees
Radians
0 π
Perfect match!

Build the formula

Find the Arc Length for a circle with and .

Arc
Fraction
×
Full
Circumference
Formula built successfully!

Paint the area

Radius (Total Area = ).
Tap slices to create a sector area of .

Current Area
Perfect slice!
🏆

Master of Circles!

You've explored central angles, radians, arc lengths, and sector areas.