Hi Mark,

Draw a straight line from the origin 171 m long on
the x-axis(or y-axis),then draw a second one 219m long(the lines
will overlap).

Select the whole model and run the scale command.

Select endpoint on the origin as origin point,then select the
endpoint of the 219m long line as first reference point.

Move the cursor to the endpoint of the 171m line to select
the second reference point and release the mouse button.