arc area, arc length, chord length calculator

radius (r):
arc angle (a):
arc area:
arc length:
chord length:

1. circle area = π * r2

2. circumference = 2 * π * r

3. arc area (shaded) = r2 * (a - sin(a)) / 2

4. arc length = r * a

( Note: the unit is radians. )