From the Copy window, select Surfaces and Rotation.
Enter an angle of -60 degrees. Since the rotation may be done in 2D, choose
the option Two Dimensions. The center of the rotation is the intersection
of the axes, namely, point (200, 0). Be sure the Do Extrude menu is
in the No mode.
Click Select and select all the surfaces except those defining the
elbow of the pipe. Press ESC when the selection is finished.
Figure 18. Geometry of the two pipes
and the auxiliary lines