Theorem 5.8c: The area of an {n/k} star inscribed in a
circle of radius r is
nr2sin(180/n)cos(180k/n)sec(180(k-1)/n)
proof 6: The area of the star could also be expressed as
nrssin(90 - 180k/n)
by using the angle at Pk in
Theorem 5.1a.
= nr2sin(180/n)sec(180(k-1)/n)sin(90 - 180k/n)
using Theorem 4.3
= nr2sin(180/n)sec(180(k-1)/n)cos(180k/n)
Return to text
Proof 1
Proof 2
Proof 3
Proof 4
Proof 5