For example, if you want your circle to be 4 inches (10 cm) across, then your desired radius would be 2 inches (5. 1 cm) since the radius is equal to half of the diameter. Therefore, you’d cut the piece of string to be about 3–4 inches (7. 6–10. 2 cm) long so you have extra string on each end to tie the loops with.
When you’re finished tying the loops, you can measure the length of the string to determine what the exact radius of your circle will be. If the radius is too short, you can always cut a longer piece of string and try again.
If you’re drawing your circle onto a piece of thick material, like foam poster board or canvas, you can skip this step. If you don’t have anything to use as a base under your sheet of paper, you can try holding the pin in place on the paper with your fingers instead.
It doesn’t matter what end of the string you wrap around the pin. Just make sure the loop on the other end is big enough to wrap around a pencil.
You don’t have to use a pencil to draw your circle—you can use a pen, marker, colored pencil, or another drawing utensil as long as the loop fits around it.
Don’t pull on the string too hard or you could pull the pin out.
If you don’t keep the string taut, you won’t end up with a perfect circle. If your hand slips and you make a mistake, just erase what you’ve drawn and start over.
