# Rotation precision

Question asked by John Sutherland on Sep 2, 2008
Latest reply on Sep 5, 2008 by John Sutherland
My design rule specifies a trapezium with parallel sides horizontal and other sides sloping inward at rate of 1:20 to vertical.

This is a perfectly reasonable rule and I can sketch the trapezium with sufficient precision by specifying the slope as 2 deg 87 min.

However I then want to rotate the trapezium until one sloping side is Vertical.

Because 1:20 is not an integral number of degrees or radians, I can rotate to nearly vertical but not to vertical. The line's property manager shows the x ordinates of the two ends of the line as being slightly different at 7 decimal places.

How can I get the line vertical?