Diagram of the method of drawing a pentagon within a circle, using Euclid's (330-275 BC) theorems. Euclid's contribution to mathematics has been a major influence for over 2,000 years. His 'Elements of Geometry' incorporated previous works in mathematics as well as Euclid's own findings. The writings deal with plane geometry; solid geometry, including the five Platonic solids; and the theory of numbers, including a proof that there are an infinite number of primes. It was not until the 19th century that mathematicians realised other kinds of geometry exist. Illustration from 'The first six books of the Elements of Euclid: in which coloured diagrams and symbols are used instead of letters for the greater ease of learners' by Oliver Byrne, published in London in 1847.
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