Subscribe to our RSS feed
or
follow us on Twitter.

From theFun Factfiles, here is a Fun Fact at the Medium level:

One, Two, Three, Pi

Figure 1

Here's an interesting formula:

Arctan(1) + Arctan(2) + Arctan(3) = Pi.

(Everything's in radians, of course).

Presentation Suggestions:
Challenge students to prove this fact.

The Math Behind the Fact:
The Figure contains a hint;
check that the angles of the three triangles at their
common vertex add to Pi. Can you find a similar
proof for the following equation?

Arctan(1/2)+Arctan(1/3) = Pi/4.

How to Cite this Page:
Su, Francis E., et al. "One, Two, Three, Pi."
Math Fun Facts.
<http://www.math.hmc.edu/funfacts>.