x(t) = a cos(t) y(t) = a sin(t)

x^2 + y^2 = a^2 and -p/2<=tan^(-1)(x, y)<=p/2

r(θ) = a

(for a circlular arc with center at the origin, radius a, and central angle p centered around the positive x-axis)

algebraic | open | parametric | polar | quadratic | simple

r = a

2 a sin(p/2)

s = a p

d = 2