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The first stage is to draw two squares next to each other. Draw a straight line at least 3 times the length you want the side of your pentagon to have, and mark two points a and b this length apart in the middle. Then set your compass to this length and mark the points c and d equal distances either side. Set your compass wider than a to b, and using centres b and c draw a perpendicular at a. And draw another perpendicular at b.
Set your compass to a to b again and mark and draw the first square. Set the compass to a to d and draw a second one on top. Draw a diagonal in this rectangle.
Draw a circle in the centre of the rectangle with the same width. The point e is the intersection of the circle with the diagonal, and the distance a to e, if a to b is 1, is the square root of 5, divided by 2, plus ½. Set your compass to the distance between a and e, and draw two intersecting arcs centered on a and b. Call this intersection f.
Set your compass to the distance between a and b for the last time, and draw intersecting arcs centered on a, b and f to find the last two corners. Join the intersections and you have your pentagon.
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