# To Accumulate a Rate — Integrate!

Teaching High School Mathematics

# History Included part 5 (Thales – Chapter 4)

I’m reading, “A History of Mathematics,” by Carl Boyer. I’m blogging about things that I think are interesting, things that I think we should teach, or areas where learning might increase by including interesting history surrounding the topic.

Chapter 4 – Ionia and the Pythagoreans

“Thales is the first man in history to whom specific mathematical discoveries have been attributed.” – Boyer This quote made me think that having a historical mathematical timeline in my classroom would be cool. I have the men of mathematics app on my ipad that is fashioned after the old poster made by IBM. I wish I could get my hands on one of those posters… but a handmade one will have to do. How great would it be for students to see the timeline of mathematical discoveries and contributors on the wall. Any student or I could refer to it when talking about mathematical history. Apparently, Thales is going to be the first guy on the timeline. I might make the timeline and then have students add the important characters. I’ll post if/when I come up with something. I think this might be a great assignment for my problem solving class to do next year.

Legend has it that Thales is responsible for a few geometrical theorems.

1. An angle inscribed in a semicircle is a right angle.
2. A circle is bisected by a diameter.
3. The base angles of an isosceles triangle are equal.
4. The pairs of vertical angles formed by two intersecting lines are equal.
5. If two triangles are such that two angles and a side of one are equal respectively to two angles and a side of the other, then the triangles are congruent.

Maybe it was Thales or maybe it wasn’t, but that adds some mystery to the history. Now I can say to my Geometry students, “Can you prove the Thales theorems? “