The TikZ and PGF Packages
Manual for version 3.1.9a
Part III TikZ ist kein Zeichenprogramm
by Till Tantau
\usetikzlibrary {angles,calc,quotes}
\begin{tikzpicture}[angle radius=.75cm]
  \node (A) at
(-2,0)     [red,left]   {$A$};
  \node (B) at
( 3,.5)    [red,right]  {$B$};
  \node (C) at
(-2,2)     [blue,left]  {$C$};
  \node (D) at
( 3,2.5)   [blue,right] {$D$};
  \node (E) at
(60:-5mm)  [below]      {$E$};
  \node (F) at
(60:3.5cm) [above]      {$F$};
  \coordinate (X) at
(intersection cs:first line={(A)--(B)}, second
line={(E)--(F)});
  \coordinate (Y) at
(intersection cs:first line={(C)--(D)}, second
line={(E)--(F)});
  \path
    (A) edge
[red, thick]  (B)
    (C) edge
[blue, thick] (D)
    (E) edge
[thick]       (F)
      pic
["$\alpha$", draw, fill=yellow]   {angle
=
F--X--A}
      pic
["$\beta$",  draw, fill=green!30] {angle
=
B--X--F}
      pic
["$\gamma$", draw, fill=yellow]   {angle
=
E--Y--D}
      pic
["$\delta$", draw, fill=green!30] {angle
=
C--Y--E};
  \node at
($ (D)!.5!(B) $) [right=1cm,text width=6cm,rounded corners,fill=red!20,inner sep=1ex]
    {
      When
we
assume
that
$\color{red}AB$
and
$\color{blue}CD$
are
      parallel, i.\,e., ${\color{red}AB} \mathbin{\|} \color{blue}CD$,
      then
$\alpha =
\gamma$
and
$\beta =
\delta$.
    };
\end{tikzpicture}