Sketch to Scale

Hello,

Is it possible to create outlines of elements using a sketch to scale tool?

If i have a 50m wide excavation, i have to scale it using the measure tool, then trace the length. 
I do a lot of circular excavations and it's not fun tracing circles.

1. Circular outline
2. Rectangular Outline
3. Polyline (start at a point, then provide length and degrees to move to next point.)

thanks