1.Select the Curve Modeling tab from the top Ribbon Bar.

2.Now select the Rectangle command.

3.Turn on Grid snap and turn off all other object Snaps. Object Snap toggles are located on the Status Toolbar at the bottom of the display.

4.For the first corner of the rectangle, select the lower left grid point location shown below or type -1.5, 0, -1.5 in the Command Prompt and press <Enter>.

5.For the second corner of the rectangle, select the upper right grid point shown above or type 3,3 in the Command Prompt and press <Enter>.  This will create a rectangle 3" square.

6.Now select the rectangle you just drew and then from the tab select the Extrude Mesh command.

7.Now drag the cursor over to the and select the grid point at 4.5 or just enter 4.5 in the command prompt and press <Enter>.