I don't know about you, but when I try to draw circles by hand, they end up looking more like mangled potatoes than anything approaching geometric perfection. Whether you're drawing or doing geometry, these tricks will help you draw the perfect circle without the aid of a compass. By using a few household items and a little ingenuity, you can make a perfect circle without having to search or shop for any specialised equipment.
Search your house for objects you may have with a flat circular surface -- cans, drinking glasses, CDs, and so on. If you find something that's the right size, you can trace it. If you don't have anything suitable to trace, go on to step 2.
Cut a piece of string a bit longer than you want the radius of your circle to be. Tie one end of the string to your pin, screw, or nail, and tie the other end around your pencil.
Place the pin, sharp side down, where you want the centre of your circle to be. Holding the string taut, guide the pencil around the pin to make a circle.
Hold the pencil with your thumb and forefinger as far down as you want the radius of your circle to be.
Place the hand that's holding the pencil, thumbnail side down, where you want the centre of your circle to be.
Use your free hand to slowly rotate the paper around the point where you are holding the pencil, with the tip of the pencil touching the paper. Take care not to move your pencil hand. When you have rotated the paper completely, you will have a circle.