14+ Concurrent Geometry Pics

14+ Concurrent Geometry
Pics. Concurrent lines are lines that intersect in one point. I was wondering how to prove euclid's theorem:

Concurrent lines -GEOMETRY from image.slidesharecdn.com

Triangle altitudes are concurrent (orthocenter). This fact holds true in absolute geometry, and i would like to see an elementary synthetic proof not using thus their projections to $\pi$ are concurrent. This view of projective geometry makes it relatively easy to answer questions of concurrence and for example, what does a collection of concurrent lines in projective space look like?

A concurrent variant of skiplists is implemented in concurrentskiplistmap, providing an expected average log(n) time cost for the containskey, get, put and remove operations and their variants.

The point p is called the point of concurrency. Write concurrent lines and their and their point of concurrence from the given figure, we have: Combinatorial computational geometry deals with interaction of basic geometrical objects: The four types of points of concurrency in triangles: