The classical way of inscribing a regular pentagon in a circle is discussed in Book IV, Proposition 11 of Euclid’s Elements. The method of Euclid is a bit complicated since it requires first to draw a golden triangle (a 72-72-36 triangle) and then to inscribe the triangle in the given circle. In this post I… Continue reading A Very Easy Method to Inscribe a Regular Pentagon in a Circle

# Category: math

## Lill’s Method and Geometric Solutions to Quadratic Equations With Complex Roots

I already wrote a paper called “Lill’s Method and Graphical Solutions to Quadratic Equations” that shows how to solve quadratic equations using Lill’s method. In this post I want to show an alternative way of solving quadratic equations that have complex or imaginary roots. This method was briefly mentioned in the paper “Geometric Solution of… Continue reading Lill’s Method and Geometric Solutions to Quadratic Equations With Complex Roots

## The Hexagram/Six Pointed Star/Star of David and the Golden Ration

Many people that are familiar with the golden ratio ( Φ = 0.5(1+ 50.5) which is about 1.61803), know that it appears very often in the proportions of the pentagon and the pentagram. In this post I want to present a diagram that connects the golden ratio with the regular hexagram or the six pointed… Continue reading The Hexagram/Six Pointed Star/Star of David and the Golden Ration

## Top 3 Math Books Everybody Should Buy

In this review I will go over a short list of math books that I consider to be useful for most people interested in the subject of math. The books included in this list should provide a general math education. I tried to include books that cover the following aspects of general math education: introduction… Continue reading Top 3 Math Books Everybody Should Buy

## Symbolism: Allegory of Arithmetic by Laurent de La Hyre

In this post I want to discuss the symbolism found in the painting “Allegory of Arithmetic” by the baroque painter Laurent de La Hyre. This painting belongs to La Hyre’s series of paintings on the liberal arts. Since Martianus Capella ( 5th century AD), the seven liberal arts were divided in trivium (grammar, logic/dialectics and… Continue reading Symbolism: Allegory of Arithmetic by Laurent de La Hyre