# Intersection between line and circle (tkz-euclide)

Now once, again I am trying to reconstruct one of these odd images in tikz.

Now, what is supposed to show, is only the triangle, the angle, and the line CD. My attempt to do this is shown below

\documentclass[10pt,a4paper]{article}
\usepackage{amsmath}
\usepackage[dvipsnames*,svgnames]{xcolor}
\usepackage{tkz-euclide}
\usetkzobj{all}
\usepackage{mathtools}

\begin{document}
\begin{tikzpicture}
\tkzDefPoint(0,0){A}
\tkzDefPoint(4,1){B}
\tkzDefMidPoint(A,B) \tkzGetPoint{M}
\tkzInterLC(A,B)(A,1pt) \tkzGetPoint{D}
\tkzDefLine[orthogonal=through D](A,D)
\tkzInterLC[R](D,tkzPointResult)(I,M) \tkzGetFirstPoint{C}
\tkzDrawPolygon(A,B,C)
\tkzDrawLinesegment(C,D)
\end{tikzpicture}
\end{document}


I keep getting an error using this code. It has to do with the circle I am trying to create around A. Could anyone please help me, to spot and fix the mistake in my code?

If you want to specify the circle in \tkzInterLC using the center and the radius, you have to supply the [R] option. To get the intersection, use \tkzGetFirstPoint or \tkzGetSecondPoint as appropriate:

\documentclass{standalone}
\usepackage{tkz-euclide}
\usetkzobj{all}

\begin{document}
\begin{tikzpicture}
\tkzDefPoint(0,0){A}
\tkzDefPoint(4,1){B}
\tkzDefMidPoint(A,B) \tkzGetPoint{M}
\tkzInterLC[R](A,B)(A,1cm) \tkzGetSecondPoint{D}
\tkzDefLine[orthogonal=through D](A,D)
\tkzInterLC(D,tkzPointResult)(M,A) \tkzGetSecondPoint{C}
\tkzDrawPolygon(A,B,C)
\tkzDrawSegment(C,D)
\tkzDrawPoints(A,B,C,D,M)
\tkzLabelPoints(A,B,C,D,M)
\end{tikzpicture}
\end{document}

• you are headache reliever! – Pouya Feb 7 '18 at 14:09