If a ray r emanating from an exterior point of triangle ABC intersects side AB at any point between A and B, then r also intersects side AC or side BC
137990
Justify each step in the following proof of Proposition 3.9 (a). I like to know if I'm in the right track and I'm also missing a few of them
152509
Does there exist a side-rational triangle of area $1$?
119111
How does this equality on vertices in the complex plane imply they are vertices of an equilateral triangle?
18913
How to find a basis for the intersection of two vector spaces in $\mathbb{R}^n$?
142862
Intersection of an ellipsoid and plane in parametric form
156596
Prove $r^2+r_1^2+r_2^2+r_3^2=16R^2-a^2-b^2-c^2$ for a triangle with sides $a$, $b$, $c$, circumradius $R$, inradius $r$, exradii $r_1$, $r_2$, $r_3$
88555
About the point $P$ inside a square $ABCD$ satisfying $BP = BC$ and $\angle APD = 90^\circ$
116153
The Notorious Triangle Problem
120641
Intersection of three vector subspaces
134722
Intersection of straight line and circle
64861
Intersection of open affines can be covered by open sets distinguished in *both*affines
216
In a $\triangle ABC,a^2+b^2+c^2=ac+ab\sqrt3$,then the triangle is
151716
Reflection over a line $y= ax + b$ - How to find the according point?
101476
If $A$, $B$ and $C$ are the angles of a triangle then find the value of $\Delta$
24147
$AG,AF$ are perpendiculars to the internal bisectors $CG,BF$ and $GF$ extended intersects $AB,AC$ at $H,I$
90056
A synthetic geometrical proof required on a result regarding Isosceles triangles.
20335
If $A\subset B$ then $\bar{A}\subset \bar{B}$