One of the most talked about new sketch functions in SOLIDWORKS 2009 is “Numeric Sketch Input”. Why? It is a big time saver -you can add sketch entities and add dimensions all in one command. [Assuming you are the kinda guy who likes to add dimensions this early in the design process.]
Sadly when this new mode is on, the “A” key cannot be used to toggle from “line” mode to “tangent arc” mode.
All is not lost. The older method of changing modes still works. Draw your first line, then as you are drawing the second line go back and touch the starting point of this line, you will automatically switch to “tangent arc” mode.