<?xml version="1.0" encoding="utf-8"?>
<!-- Geometry Snacks #28 (Prove it!), drawn by hand as a ruler-and-compass construction.
     The right angle is at the hidden point A: a hidden segment AX along the bottom, the perpendicular to it at A, cut by
     the circle about A through X at Y, so AY is a hidden segment up the left. The two handles slide along them: C along
     AX, B along AY, so ABC is right-angled at A whatever its legs. The incircle is the circle about I, where the
     bisectors of the angles at A and at C meet, through the foot of the perpendicular from I to AC. The square at A
     is the mark of the right angle. -->
<Drawing Version="1">
  <Viewport Left="-0.7" Top="6.7" Right="6.7" Bottom="-0.7" />
  <Scene Left="-0.7" Top="6.7" Right="6.7" Bottom="-0.7" />
  <Styles>
    <PointStyle Name="Handle" Size="15" Fill="#FFFFFFFF" Color="#FF1E1E1E" StrokeWidth="2.5">
      <Dark Fill="#FF1E2228" Color="#FFF2F2F2" />
    </PointStyle>
    <ShapeStyle Name="Frame" Color="#FF000000" StrokeWidth="3" IsFilled="false">
      <Dark Color="#FFE8EBF0" />
    </ShapeStyle>
    <ShapeStyle Name="RedFrame" Color="#FFEF303F" StrokeWidth="3" IsFilled="false">
      <Dark Color="#FFF0616C" />
    </ShapeStyle>
    <LineStyle Name="Ink" Color="#FF000000" StrokeWidth="3">
      <Dark Color="#FFE8EBF0" />
    </LineStyle>
  </Styles>
  <Figures>
    <FreePoint Name="A" Visible="false" Locked="true" X="0" Y="0" />
    <FreePoint Name="X" Visible="false" Locked="true" X="6" Y="0" />
    <Segment Name="AX" Visible="false">
      <Dependency Name="A" />
      <Dependency Name="X" />
    </Segment>
    <PerpendicularLine Name="up" Visible="false">
      <Dependency Name="AX" />
      <Dependency Name="A" />
    </PerpendicularLine>
    <Circle Name="cx" Visible="false">
      <Dependency Name="A" />
      <Dependency Name="X" />
    </Circle>
    <IntersectionPoint Name="Y" Visible="false" Algorithm="IntersectLineAndEllipse1">
      <Dependency Name="up" />
      <Dependency Name="cx" />
    </IntersectionPoint>
    <Segment Name="AY" Visible="false">
      <Dependency Name="A" />
      <Dependency Name="Y" />
    </Segment>
    <PointOnFigure Name="C" Style="Handle" X="4.2" Y="0" Parameter="0.7">
      <Dependency Name="AX" />
    </PointOnFigure>
    <PointOnFigure Name="B" Style="Handle" X="0" Y="3.12" Parameter="0.52">
      <Dependency Name="AY" />
    </PointOnFigure>
    <Polygon Name="ABC" Style="Frame">
      <Dependency Name="A" />
      <Dependency Name="B" />
      <Dependency Name="C" />
    </Polygon>
    <AngleArc Name="rightAngle" Style="Ink" Radius="30">
      <Dependency Name="A" />
      <Dependency Name="C" />
      <Dependency Name="B" />
    </AngleArc>
    <AngleBisector Name="bisectorA" Visible="false">
      <Dependency Name="A" />
      <Dependency Name="C" />
      <Dependency Name="B" />
    </AngleBisector>
    <AngleBisector Name="bisectorC" Visible="false">
      <Dependency Name="C" />
      <Dependency Name="B" />
      <Dependency Name="A" />
    </AngleBisector>
    <IntersectionPoint Name="I" Visible="false" Algorithm="IntersectLineAndLine">
      <Dependency Name="bisectorA" />
      <Dependency Name="bisectorC" />
    </IntersectionPoint>
    <PerpendicularLine Name="down" Visible="false">
      <Dependency Name="AX" />
      <Dependency Name="I" />
    </PerpendicularLine>
    <IntersectionPoint Name="F" Visible="false" Algorithm="IntersectLineAndLine">
      <Dependency Name="down" />
      <Dependency Name="AX" />
    </IntersectionPoint>
    <Circle Name="incircle" Style="RedFrame">
      <Dependency Name="I" />
      <Dependency Name="F" />
    </Circle>
  </Figures>
</Drawing>
