Divide the circle in two halves with its diameter. Divide each half into equal sectors. ”Opening” the halves and inserting one into the other, one gets a shape of the same
We've used the formula for the
The model can be manufactured from wood and a stripe of leather. The latter should be picked of a different color than the wood's, so that the circumference and the rectangle's long sides were clearly distinguishable. In one of the two parts, one sector should be divided in two halves — so that the external pieces were halves of standard sectors. Then the shape obtained would look more like a rectangle when put together, otherwise — like a parallelogram.
To use the formula for the
Now unwrap all the stripes at once and the circle turns into almost a triangle. "Almost" — because its legs are not straight lines, but are comprised of steps.
Several formulae for finding the
We've used a formula for the