Hi Ekaterina!
Thanks for your questions! I'm not quite sure what you mean, but if you want to change how you draw a pyramid (a solid Brep shape), check the draw options from the Rhino Command prompt when drawing it. Click on "Mode=Circumscribed" to change it to "Mode=Inscribed" to change what the radius is, either to the corner or to the nearest edge. If you'd just like to draw the length of an edge and that be the base of your pyramid, click on "Edge". See attached image
Cheers!
Arie