Whenever I think of “geometry”, a protractor comes up in my mind.
When I was in primary school, I begged my mother to buy me a protractor ahaha. Don’t ask me why. I’ve always been a wierdo.
But it’s not an essential tool for geometry, you know? Because you can divide a circle into equal parts by using only your compass and ruler.
WHAT IS A PROTRACTOR
If you don’t know what a protractor is here is what Wikipedia says: “A protractor is a measuring instrument, typically made of transparent plastic or glass, for measuring angles. “
The protractor is usually a semi-circle divided into one hundred and eighty parts or a full circle divided into three hundred and sixty parts.
Basically, it’s a circular or semi-circular tool with many small lines all around the circumference. Each line marks 1° (one degree). First real protractors were made more than five hundred years ago and they were used for map preparations and navigational charts for high latitude usage.
DO I USE IT?
The times that I’ve used a protractor in my Islamic geometry drawings can be counted on the fingers of one hand. There is nothing better than being able to divide a circle into equal parts with the use of a compass and straight edge. No shortcuts.
I don’t know why, but to me it feels like cheating, you get me? but then in 2019 something changed.
AN INTERESTING POINT OF VIEW
Last year I attended the Islamic geometry summer school in Spain. There, I saw Ameet (aka Ambigraph) using a tool he designed and made himself to speed up and make more accurate the process of making certain specific regular circle divisions which are useful in Islamic geometry.
I was shocked. And OF COURSE, I had to ask him what he was doing!!
He was pretty calm about that. He said that if you already know how to divide a circle into equal parts with a compass and ruler, sometimes shortcuts allow you to explore new patterns without spending your time making the same circle division over and over again. Now, THAT MADE SENSE!
I’m not saying that I use protractors now, but I will feel less guilty if I do.
What about you? Do you use the protractor when drawing Islamic geometry? How do you feel about that?
The Use of Protractor in Islamic Geometry
June 4, 2020