Descartes’ theorem, a cornerstone of geometry, defines the relationship between four mutually tangent circles. But for centuries, generalizing the equation to more than four circles had eluded ...

Circle theorems are used in geometric proofs and to calculate angles. Part of Maths Geometry and measure. Save to My Bitesize Save to My Bitesize Saving Saved Removing Remove from My Bitesize.

Students are often unsure why angles in the same segment of a circle have to be equal. Colin Foster explains how to make it ...

It turns out that to be rectifiable all circles need to pass through some other common point. The second main result is a complete description of geometries in R³ in which all the geodesics are ...

Circle theorems are used in geometric proofs and to calculate angles. Part of Maths Geometry and measure. Save to My Bitesize Save to My Bitesize Saving Saved Removing Remove from My Bitesize.

Descartes’ theorem, a cornerstone of geometry, defines the relationship between four mutually tangent circles. But for centuries, generalizing the equation to more than four circles had eluded ...