Elements is the oldest surviving large-scale logical written work of Mathematics. Elements is a collection of 13 books attributed to the ancient Greek mathematician Euclid, who lived in Egypt in 300 BCE. It has proven to be very important in the development of logic and modern science.
Using only a pencil, ruler and compass, Euclid wrote 465 theorems, as well as defi nitions, postulates, propositions and mathematical proofs, all of which are contained in Elements.
The defi nition of parallel lines as a pair of straight lines in a plane that do not meet is Defi nition 23 in Book I of Euclid’s Elements. What do you think defi nitions 1–22 could be?
Study the picture to the right. The sides of the Leaning Tower of Pisa are parallel to each other, and the lines marked p and q are also parallel.
Find the measure of the angles marked with the letters A, B, C, D, E, F and G, without using a protractor.
p 80 G° D C
B
E
F A q
Section A Introducing concepts and building skills