The Circle by Alfred Posamentier & Robert Geretschläger
I have had the pleasure to read, from beginning to end, a new book describing the multiple attributes of that most common of geometric figures, the circle. I say that as a person with some scientific background, but with very little knowledge or experience in the field of mathematics.
Now retired, my profession was in Medicine with my specialty in the ocular field, the eye. It is interesting that I was asked to review a book about the very geometric figure that I spent my entire productive life looking at every day, a spherical organ with circles in a plane in that sphere.
The journey starts out with an excellent discussion of the many aspects of the circle as we know it. The geometry of the lines within, intersecting with, and tangential to it, as well as the relation of circles within and tangential to each other makes for a fascinating discussion. There is also the Reuleaux triangle, which doesn’t look like a circle, but has many of the geometric and practical attributes of a circle. The Mazda automobile with the “Rotary Engine” is something which most of us remember, but it could have been called the Reuleaux triangle engine, a triangle acting like a circular crankshaft. The book has many such revelations that apply to our everyday lives that I did not think of before.
The many diagrams and formulae found in the explanatory discussions reflect the incredible attention that science and mathematics has devoted to the circle over the millennia. There are many references to the ancients with their stories that bring a feeling of the passion that was devoted to the solving of the mathematical geometry of the circle. The Greek mathematician Archimedes (287-212 BCE) using sand and a sharp stylus as a compass, designed and developed war machines used against the Romans. He lost his life despite the edict of victorious Rome to spare the life of this invaluable scientist and mathematician. An unsuspecting and uninformed Roman Legionnaire beheaded Archimedes while he was studying by drawing circles in the sand.
Early astronomers and theologians used the circle to evolve and describe their respective fields. Artists such as Escher and Rembrandt used the geometry of circles in their art. The engineers in the space program of today, the engineers designing the robotic technology for medicine, and pure mathematicians are all working to make our lives better today using the knowledge of the math and geometric principles of the circle.#