Games and Hobbies

Materials:
Scrap cardboard- corrugated cardboard or a shoe box top works well
Strip of cardboard or sturdy paper
Pencil
2 push pins
Straight edged object or ruler

Trace the outline of a circular object.

Put the paper on top of the scrap cardboard.
Push the 2 push pins on the line of the circle opposite each other as shown in the picture.

Cut a strip of cardboard or sturdy paper.
Insert the pins at a distance a little more than ½ of the circle.

Remove one of the push pins from the cardboard strip.
Insert the remaining pin into one of the holes you made on the circle.

Put the tip of the pencil through the other hole. * a pen was used in the guide to see the marks but pencil marks can be erased.
Swivel the strip and mark the arc around the middle in each direction.

Push the pin through the other hole you made on the circle.
Swivel the strip to mark the arc around the middle in each direction.

Result – 2 X’s

Use a straight edge to make a line inside the circle connecting the center of the X’s.

Result

Push the pins through the ends of the line where they touch the circle.

Push a pin through a hole in the cardboard strip and through one of the holes you just make.
Insert the pencil in the other hole, swivel the cardboard strip and mark the arc at the top and bottom.

Insert the pin in the other hole and repeat.

Result – 2 X’s where the arcs you just made meet

Align a straight edge to the center of the X’s you just made.
Mark the spot where the straight edge meets the line in the middle.

That’s it! You just marked the center of the circle.

Make a dot in the center and erase all the pencil markings.