Theorem II: For an equilateral triangle, the ratio of the areas of the circumscribed (outer) and inscribed (inner) circles is 4:1. The area of the ring between the circles is 3 times the area of ...

The probability that a random chord in a circle is longer than the side of an equilateral triangle inscribed in the circle is proved to be 1⁄3 (top), 1⁄2 (middle) and 1⁄4 (bottom).

Have you ever wondered why the cover of a manhole is nearly always round? Why isn’t it oval or square? Reuleaux curve based on an equilateral triangle. Reuleaux curves based on the pentagon (top ...