Ellipse and Circle Love

Geometry Level pending

A circle of radius \(r\) passes through both foci of, and exactly four points on, the ellipse with equation \(x^2 + 16y^2 = 16\). The set of all possible values of \(r\) is an interval \([a,b)\). What is \(a + b\)?


This is a problem from the 2015 AMC (12 A #21).
×

Problem Loading...

Note Loading...

Set Loading...