This SVG example illustrates how to create an angle with oriented arrowhead markers and a Greek letter as its label.

LabeledAngleWithMarkers.svg

<svg width="400" height="400" xmlns="http://www.w3.org/2000/svg">
  <defs>
    <marker id="idArrowhead" markerWidth="9" markerHeight="9" refX="8" refY="4" orient="auto">
      <path d="M 0,0 L8,4 L0,8 Z" fill="black" stroke="black" />
    </marker>
  </defs>
  <circle cx="200" cy="200" r="150" fill="none" stroke="gray" />
  <path d="M 200,200 L350,200" stroke="gray" fill="none" marker-end="url(#idArrowhead)" />
  <path d="M 200,200 L306,94" stroke="gray" fill="none" marker-end="url(#idArrowhead)" />
  <text x="230" y="190" font-size="20" fill="black">&#945;</text>
</svg>

Output