There is something special about a triangle with sides of 8, 15 and 17.
The sides of the triangle are tangents to the circle.
You might like to look at how to construct an inscribed circle in the Thesaurus (Search under constructions).
The angle between a tangent and a radius is 90^o.
The centre of the inscribed circle lies on the bisector of the angle between the two tangents from any point outside the circle.
The two tangents to a circle from the same point are equal.