Is the locus of a point with the ratio of its distances from two given points being a constant $\neq 1$ always a circle?
54228
Equation of a line maintaining equal ratio distance between two points.
71074
The locus of the intersection point of two perpendicular tangents to a given ellipse
100404
Angle subtended at the centre by a segment of a circle
144901
Tangent to a circle through a point
118663
Looking for a Simple Argument for "Integral Curve Starting at A Singular Point is Constant"
115677
Prove the equality of circle's areas
129721
Expected value of the distance between 2 uniformly distributed points on circle
36888
How to prove that the limit of an $n$-gon is a circle?
157171
Gauss circle problem : a simple asymptotic estimation.
137283
Is there geometric proof for the equation of hyperbola using only constant distance from two foci definition?
88317
Let gh be a chord of a circle ω which is not a diameter, and let A be a fixed point on gh
117595
Minimum Modulus Principle for a constant fuction in a simple closed curve
85242
Deciding whether two metrics are topologically equivalent in the space $C^1([0,1])$
136973
What does the locus of $M$ form?
37448
Two Circles and Tangents from Their Centers Problem
61262
Is $\cot(z)-\frac1z$ bounded on a given circle?
84189
Is $\mathbb{C}$ equal to $\mathbb{R}^2$?