How to get the perimeter of a circle from 8r to 2 $pi$ r
2786
The staircase paradox, or why $\pi\ne4$
148233
Proof that every circle has the ratio of $\pi$
18836
Complex integral over a circle
63802
Parametric Equation of a Circle Using a Line
132402
Find 2nd leg of right triangle with known leg and perimeter
64384
Finding center and radius of circumcircle
87850
How can I find the points at which two circles intersect?
81777
Sum of radii of intersecting circles internally tangent to another circle
148746
Calculating $\int\frac{e^{iz}}{z}\, dz$ on the semi-circle given by $re^{i\theta}$ where $\theta:\,0\to\pi$
143967
Finding an equation for a circle given its center and a point through which it passes
118793
Finding circle circumscribed in spherical triangle
29517
How to find continued fraction of pi
115450
Find the arc length of lemniscate $r=2(\cos(2\theta))^{1/2}$
83596
A simple proof that a polygon circumscribing a circle overestimates its perimeter
147410
ArcTan(2) a rational multiple of $\pi$?
71960
How to determine the equation and length of this curve consistently formed by the intersection of Circles
130665
Determine radius of a rounded rectangle