To draw an arc you need 3 mouse clicks. The first click defines the origin of the arc, the second click defines the end of the arc. After the two initial clicks move the mouse to define the radius of the arc and finally click again to complete the arc creation action.
Actions and modes of the tool
Press the [ESC] key to exit the drawing action.
Double clicking on the page or the work environment will set the document view to "full-page".