You can find any tool by the Menu Structure HERE: https://turbocaddoc.atlassian.net/wiki/display/TC20UG/Menu+Structure
You can find the menu location of any tool by name HERE: https://turbocaddoc.atlassian.net/wiki/display/TC20UG/Tools+Mapped+to+Menus
Arc - Center and Radius
Creates an arc by defining its center, a point on its circumference, and the start and end angles.
- Select the arc centerpoint and a point on the circumference of the circle from which the arc will be cut. You can also specify the radius, diameter, or circumference in the Inspector Bar.
- A dotted line appears from the centerpoint. Move the cursor to set the arc start angle, or enter the angle in the Inspector Bar.
- Move the cursor counterclockwise to draw the arc, or enter the end angle or arc length in the Inspector Bar.