If the direction lines aren’t already visible, they appear. The length and slope of the direction lines determine the shape of the curve. If you’ve used other vector based software like Inkscape or FreeHand…chances are you feel like they draw more intuitive than Illustrator. Click where you want the line to begin. To complete the shape, double-click the first point you placed.

Then click OK. Click once to create your first point. To alter a curved segment after you create it, follow these steps: Choose Select→Deselect to ensure that no objects are selected. Each double-click creates a corner point with a straight line in between. Choose the Direct Selection tool and click the last anchor point created.
Then double-click the center of each of the other circular guides. I haven’t spent time in those programs.

So I’m not going to debate about it. In the dialog box, specify the Length and the Angle of the line. How to Turn a Straight Line Into a Curved Line in Illustrator…intuitively. You create a curve by adding an anchor point where a curve changes direction, and dragging the direction lines that shape the curve.
Position the pointer where you want the line to begin, and drag to where you want the line to end. If you want to fill the line with the current fill color, select Fill Line.