Code for video "Right angle symbol with Tikz using distance modifiers"

2nd May 2023

Code to accompany YouTube Video: https://youtu.be/EL4rYOrNydI

Example 1

\documentclass[10pt]{article}
\usepackage{tikz}
\usetikzlibrary{calc}

\begin{document}

\begin{tikzpicture}[scale=1]

	% Grid.
	\draw [step=1cm,gray, ultra thin] (0,0) grid (5,5);
	\draw [gray, thick] (0,0) -- (5,0);
	\draw [gray, thick] (0,0) -- (0,5);

	% Triangle.
	\draw [purple, thick] (0,0) -- (4,0) -- (0,4) -- cycle;

	% Right angle symbol.
	\draw [purple, thick] (0,0) rectangle (0.4,0.4);

\end{tikzpicture}

\end{document}
			

Example 2

\documentclass[10pt]{article}
\usepackage{tikz}
\usetikzlibrary{calc}

\begin{document}
		
\begin{tikzpicture}[scale = 1]
		
	% Grid.
	%\draw [step=1cm,gray, ultra thin] (0,0) grid (6,7);
	%\draw [gray, thick] (0,0) -- (6,0);
	%\draw [gray, thick] (0,0) -- (0,7);	
	
	% Triangle
	\coordinate (a) at (0,0);
	\coordinate (b) at (30:6);
	\coordinate (c) at (60:{6 / cos(30)});	
	\draw [purple, thick] (a) -- (b) -- (c) -- cycle;
	
	% Right angle symbol.
	\coordinate (d) at (30:5.6);
	\coordinate (e) at ($ (d)!0.4cm!90:(b) $);
	\coordinate (f) at ($ (e)!0.4cm!90:(d) $);
	\draw [purple, thick] (d) to (e) to (f);
	
	% Dots.
	\filldraw (a) circle [radius=0.05];
	\filldraw (b) circle [radius=0.05];
	\filldraw (c) circle [radius=0.05];
	\filldraw (d) circle [radius=0.05];
	\filldraw (e) circle [radius=0.05];
	\filldraw (f) circle [radius=0.05];
	
	% Dot labels.
	\draw (a) node [below left]{a};
	\draw (b) node [right]{b};
	\draw (c) node [above]{c};
	\draw (d) node [below]{d};
	\draw (e) node [left]{e};
	\draw (f) node [above right]{f};
	
	% Line Labels.
	\draw (4.5, 4.5) node [above] {A};
	\draw (1.5, 3.5) node [above] {B};
	\draw (3.0, 1.1) node [above] {C};
	
\end{tikzpicture}
	
\end{document}