[Tex/LaTex] How to draw a simple cone with height and radius with TikZ

tikz-pgf

I need to make a very simple cone with h and r (like the picture I've uploaded as example) and I can't find it in previous questions.

Simple cone

Best Answer

With arc

 \documentclass[tikz,border=10pt]{standalone}
\usetikzlibrary{calc}
\begin{document}
  \begin{tikzpicture}
    \draw[dashed] (0,0) arc (170:10:2cm and 0.4cm)coordinate[pos=0] (a);
    \draw (0,0) arc (-170:-10:2cm and 0.4cm)coordinate (b);
    \draw[densely dashed] ([yshift=4cm]$(a)!0.5!(b)$) -- node[right,font=\footnotesize] {$h$}coordinate[pos=0.95] (aa)($(a)!0.5!(b)$)
                            -- node[above,font=\footnotesize] {$r$}coordinate[pos=0.1] (bb) (b);
    \draw (aa) -| (bb);
    \draw (a) -- ([yshift=4cm]$(a)!0.5!(b)$) -- (b);
  \end{tikzpicture}
\end{document}

enter image description here

With ellipse

\documentclass[tikz,border=10pt]{standalone}
\usetikzlibrary{calc}
\begin{document}
  \begin{tikzpicture}
    \begin{scope}
     \clip (-2,0) rectangle (2,1cm);
    \draw[dashed] (0,0) circle(2cm and 0.35cm);
    \end{scope}
    \begin{scope}
     \clip (-2,0) rectangle (2,-1cm);
    \draw (0,0) circle(2cm and 0.35cm);
    \end{scope}
    \draw[densely dashed] (0,4) -- node[right,font=\footnotesize] {$h$}coordinate[pos=0.95] (aa)(0,0)
                            -- node[above,font=\footnotesize] {$r$}coordinate[pos=0.1] (bb) (2,0);
    \draw (aa) -| (bb);
    \draw (-2,0) -- (0,4) -- (2,0);
  \end{tikzpicture}
\end{document}

enter image description here

Gonzalo has kindly provided the shadings to the cylinder and I am reproducing his code (with thanks):

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shadings}

\begin{document}

\begin{tikzpicture}
\fill[
  top color=gray!50,
  bottom color=gray!10,
  shading=axis,
  opacity=0.25
  ] 
  (0,0) circle (2cm and 0.5cm);
\fill[
  left color=gray!50!black,
  right color=gray!50!black,
  middle color=gray!50,
  shading=axis,
  opacity=0.25
  ] 
  (2,0) -- (0,6) -- (-2,0) arc (180:360:2cm and 0.5cm);
\draw 
  (-2,0) arc (180:360:2cm and 0.5cm) -- (0,6) -- cycle;
\draw[dashed]
  (-2,0) arc (180:0:2cm and 0.5cm);
\draw[dashed]
  (2,0) -- node[below] {$r$} (0,0) -- node[left] {h} (0,6) ;
\draw 
  (0,8pt) -- ++(8pt,0) -- (8pt,0);   
\end{tikzpicture}

\end{document}

enter image description here

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