How many points/tangents do you need to define a unique circle?
109767
Prove that three points are enough to draw/define one and only one circle
132831
A circle with infinite radius is a line
117330
What is the name of a squircle with three, five, six or more corners?
131621
Evaluating a product of tangents
76001
Construct a fourth circle tangent to 3 circles forming a tangency chain
94212
How do I mark an angle with multiple arcs?
157171
Gauss circle problem : a simple asymptotic estimation.
63074
The equation of a family of circles passing through two given points
125597
calculator's angle answer for trig ratios that can work in more than 1 quadrant on the unit circle
39416
The space obtained by identifying the antipodal points of a circle
103714
Progressively filled circles
9351
Tangential acceleration in circular motion?
101734
$7$ points inside a circle at equal distances
138629
What are curves (generalized ellipses) with more than two focal points called and how do they look like?
37448
Two Circles and Tangents from Their Centers Problem
110352
Why is a full turn of the circle 360°? Why not any other number?
12070
Probability that n points on a circle are in one semicircle