<?xml version="1.0" encoding="utf-8"?>
<!-- Geometry Snacks #24 (What's the Angle?), drawn by hand as a ruler-and-compass construction. The figure is fixed
     by the given 52° (the asked angle is four times the given one less 180°, so nothing can move without changing
     both), so nothing is dragged.
     A circle about the hidden point O through the hidden point R; the line OR cuts it again at L, so LR is a diameter
     and its midpoint M the centre dot. The hidden point Q is on the diameter where the angle at L comes out 52°
     (PL = LR cos 52°, and LQ = 2 PL cos 52°, so Q is 2 LR cos² 52° from L). P is the point of the circle above the diameter
     equidistant from L and Q (the perpendicular bisector of LQ meets the circle there), and the circle about P
     through L cuts the circle again at S, so PL = PQ = PS. The arc at L marks the given angle between the diameter and
     PL; the red wedge at P is the asked angle between PQ and PS. The "52°" sits on the bisector of the angle at L,
     1.5 units out (three midpoints of LM and a circle about L). -->
<Drawing Version="1">
  <Viewport Left="-4.9" Top="4.9" Right="4.9" Bottom="-4.9" />
  <Scene Left="-4.9" Top="4.9" Right="4.9" Bottom="-4.9" />
  <Styles>
    <ShapeStyle Name="Frame" Color="#FF000000" StrokeWidth="3" IsFilled="false">
      <Dark Color="#FFE8EBF0" />
    </ShapeStyle>
    <LineStyle Name="Ink" Color="#FF000000" StrokeWidth="3">
      <Dark Color="#FFE8EBF0" />
    </LineStyle>
    <ShapeStyle Name="RedWedge" Color="#FFEF303F" StrokeWidth="1" Fill="#FFEF303F">
      <Dark Color="#FFD9333F" Fill="#FFD9333F" />
    </ShapeStyle>
    <PointStyle Name="Dot" Size="8" Fill="#FF000000" Color="#FF000000" StrokeWidth="1">
      <Dark Fill="#FFE8EBF0" Color="#FFE8EBF0" />
    </PointStyle>
    <TextStyle Name="Mark" FontSize="28" Color="#FF000000" FontFamily="Segoe UI" Bold="true">
      <Dark Color="#FFE8EBF0" />
    </TextStyle>
    <PointStyle Name="Anchor" Size="1" Fill="#00000000" Color="#00000000" StrokeWidth="0" />
  </Styles>
  <Figures>
    <FreePoint Name="O" Visible="false" Locked="true" X="0" Y="0" />
    <FreePoint Name="R" Visible="false" Locked="true" X="4" Y="0" />
    <Circle Name="c" Style="Frame">
      <Dependency Name="O" />
      <Dependency Name="R" />
    </Circle>
    <LineTwoPoints Name="d" Visible="false">
      <Dependency Name="O" />
      <Dependency Name="R" />
    </LineTwoPoints>
    <IntersectionPoint Name="L" Visible="false" Algorithm="IntersectLineAndEllipse1">
      <Dependency Name="d" />
      <Dependency Name="c" />
    </IntersectionPoint>
    <MidPoint Name="M" Style="Dot">
      <Dependency Name="L" />
      <Dependency Name="R" />
    </MidPoint>
    <Segment Name="LR" Style="Ink">
      <Dependency Name="L" />
      <Dependency Name="R" />
    </Segment>
    <FreePoint Name="Q" Visible="false" Locked="true" X="2.064624" Y="0" />
    <SegmentBisector Name="bisectorLQ" Visible="false">
      <Dependency Name="L" />
      <Dependency Name="Q" />
    </SegmentBisector>
    <IntersectionPoint Name="P" Visible="false" Algorithm="IntersectLineAndEllipse1">
      <Dependency Name="bisectorLQ" />
      <Dependency Name="c" />
    </IntersectionPoint>
    <Circle Name="cp" Visible="false">
      <Dependency Name="P" />
      <Dependency Name="L" />
    </Circle>
    <IntersectionPoint Name="S" Visible="false" Algorithm="IntersectCircleAndCircle1">
      <Dependency Name="c" />
      <Dependency Name="cp" />
    </IntersectionPoint>
    <Segment Name="PL" Style="Ink" Decoration="OneTick">
      <Dependency Name="P" />
      <Dependency Name="L" />
    </Segment>
    <Segment Name="PQ" Style="Ink" Decoration="OneTick">
      <Dependency Name="P" />
      <Dependency Name="Q" />
    </Segment>
    <Segment Name="PS" Style="Ink" Decoration="OneTick">
      <Dependency Name="P" />
      <Dependency Name="S" />
    </Segment>
    <AngleArc Name="given" Style="Ink" Radius="45">
      <Dependency Name="L" />
      <Dependency Name="R" />
      <Dependency Name="P" />
    </AngleArc>
    <AngleArc Name="asked" Style="RedWedge" Radius="50">
      <Dependency Name="P" />
      <Dependency Name="Q" />
      <Dependency Name="S" />
    </AngleArc>
    <!-- the "52°" on the bisector of the angle at L, 1.5 units from L: a point there is attached to, shown in a style that draws nothing -->
    <AngleBisector Name="bisector" Visible="false">
      <Dependency Name="L" />
      <Dependency Name="R" />
      <Dependency Name="P" />
    </AngleBisector>
    <MidPoint Name="H1" Visible="false">
      <Dependency Name="L" />
      <Dependency Name="M" />
    </MidPoint>
    <MidPoint Name="H2" Visible="false">
      <Dependency Name="L" />
      <Dependency Name="H1" />
    </MidPoint>
    <MidPoint Name="H3" Visible="false">
      <Dependency Name="H1" />
      <Dependency Name="H2" />
    </MidPoint>
    <Circle Name="reach" Visible="false">
      <Dependency Name="L" />
      <Dependency Name="H3" />
    </Circle>
    <IntersectionPoint Name="At" Style="Anchor" Algorithm="IntersectLineAndEllipse2">
      <Dependency Name="bisector" />
      <Dependency Name="reach" />
    </IntersectionPoint>
    <AttachedLabel Name="Given" Style="Mark" Z="1" OffsetX="-26" OffsetY="-19.55" Text="52°">
      <Dependency Name="At" />
    </AttachedLabel>
  </Figures>
</Drawing>
