# when is a point inside a triangle

Suppose $u,v$ are vectors in $\mathbbmss{R}^{2}$, and

 $x=su+tv$

for some $s,t\in\mathbbmss{R}$. Then $x$ is in the triangle spanned by $u$ and $v$ and the origin if and only if

 $s,t\geq 0,\quad s+t\leq 1.$
Title when is a point inside a triangle WhenIsAPointInsideATriangle 2013-03-22 15:22:22 2013-03-22 15:22:22 matte (1858) matte (1858) 5 matte (1858) Theorem msc 51-00 WhenIsAPointInsideAPolygon