If you have not drawn a straight line and then drawn an arc tangent to it, you can directly use the polyline command.

Input PL, draw a straight line first, then input A, draw an arc, and the drawn arc is an arc tangent to the straight line.

If you have drawn a straight line and then a tangent arc, and the radius of the arc is fixed, you can draw a straight line perpendicular to it through the endpoint of this straight line, and then draw an arc centered on the point on this straight line that looks at the radius, and you can draw an arc tangent to it.

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