Asecantis a line, ray, or line segmentthat intersectsa circleor spherein two placesand extendsoutside
of the circleor sphere.
Atangentintersectsthe circleor sphereat only one point.
In a circle,a tangentis perpendicularto the radiusthat meetsthe pointwherethe tangentintersectswith
the circle.The samethingis true for the sphere.All tangentsare perpendicularto the radii that intersect
with them.
Finally, a spherecan be slicedby an infinitenumberof differentplanes.Someplanesincludepoint , the
centerof the sphere.Otherpointsdo not includethe center.