1. Such a point of contact must be a tangency . 2. The two points of tangency are also double points. 3. This is also known as the flow tangency condition. 4. The property of tangency is defined as follows. 5. The points where these perpendiculars cross the sides are the desired points of tangency . 6. He met Kepler, and discussed with Fran�ois Vi�te two questions about equations and tangencies . 7. The complexity enters when calculating intersections at points of tangency and intersections along positive dimensional sets. 8. The point of tangency travels around the deltoid twice while each end travels around it once. 9. Figure 4 : Tangency between circles is preserved if their radii are changed by equal amounts. 10. Their points of tangency with the nine-point circle form a triangle, the Feuerbach triangle.
