# The nine-point-circle (Part I)

**Geometry**Level 5

For a triangle with sides 13, 15 and altitude 12, find the radius of the circle that pass through the following points:

The midpoint of each side.

The foot of each altitude.

The midpoint of the line segment from each vertex to the orthocenter.

If the radius can be written as \(a + \dfrac{m}{n}\), where \(a,m\) and \(n\) are positive integers, \(m<n\) and \(m\) and \(n\) are coprime. Find \(a+m+n\).

**Note**: Assume the given altitude to be through the vertex common to both the given sides