Enter a radius and central angle (degrees or radians) to find arc length, sector area, and chord length. The sector is highlighted on the diagram.
Arc length s = rθ
Sector area A = ½r²θ
Chord length = 2r·sin(θ/2)
Degrees → radians: θ_rad = θ_deg·π/180
Arc length: s = rπθ/180
Sector area: A = πr²θ/360
These are just the radian formulas after substituting θ_rad = θ_deg·π/180.
A tutor can connect arc length to the unit circle and make radian measure click for you.