A polyline is a connected sequence of line segments created as a single object. You can create straight line segments, arc segments, or a combination of the two.
• Click Menu “Draw/Pline”
• Specify first point
• Specify second point ,(A/arc)/(L/line), input A to draw arc, input L to draw line
If choose A, you may enter R radius, angle, eg: R15, 90, you will draw the arc radius as 15, the angular as 90.