To construct a rectangle with a given length and width, draw a horizontal line AB, equal to the given length. With a straightedge and triangle, erect perpendiculars from A and B, each equal to the given width. Connect the ends of the perpendiculars.

You can construct a square with a given length of side by the method described for constructing a rectangle. Another method is shown in figure 4-18. With a T square, draw horizontal line AB equal to the given length of side. With a T square and a 45 triangle, draw diagonals from A and B at 45 to AB. Erect perpendiculars from 

and B, intersecting the diagonals. Then connect the points of intersection.

Figure 4-19 shows a method of constructing a square with a given length of diagonal. Draw horizontal line AB, equal to the given length of the diagonal. Locate O at the center of AB, and lay off CD through O, perpendicular to and

slightly longer than AB. Use a T square and a 45 triangle to draw AF and EB at 45 to AB and CD, Connect AE and FB.

Figure 4-20 shows a method of drawing a square in a given circumscribed circle. Draw the diameters AB and CD at right angles to each other, and connect the points where the diameters intersect the circumference of the circle.