PELECOIDES

, or Hatchet-form, in Geometry, a figure in form of a hatchet. As the figure ABCDA, contained under the sem<*>circle BCD and the two quadrantal arcs AB and AD.

The area of the Pelecoides is equal to the square AC, and this again is equal to the rectangle BE. It is equal to the square, because the two segments AB and AD, which it wants of the square on the lower part, are compensated by the two equal segments BC and CD, by which it exceeds on the upper part. And the square is equal to the rectangle BE, because the triangle ABD, which is half the square, is also half the rectangle BE of the same base and height with it.