My Math Notebook
The converse of III.27--about equal angles and arcs. And sequencing.
Trapped in a Triangle
Learn some programming. It'll help you learn math.
Turning the Dials
Boring proof of III.27. Also, I F*cking Love Math.
Perps and Diagonals
The sum of perpendiculars to diagonals in a rectangle.
Stirring Up a Proof
A proof requiring just memory and practice.
A seemingly obvious Proposition III.12 from the Elements.
Animated setup for II.4. Then it peters out.
The Distributive Property
Some interactive work with II.1, a geometric Distributive Property.
Pappus' extension of I.47, the Pythagorean Theorem. And blobs.
Three proofs in one (I.34, I.37, and I.41). And a simulation.
Angles in a Triangle
Euclid's proof (I.32) that a triangle's angle measures have a sum of 180\(^\circ\).
Proof of a 2005 Math Olympiad problem.
Proof using SAS and congruent corresponding angles.
Interactive demo and proof using Midsegment Theorem.
A musical pattern in the Fibonacci numbers.
Spacetime graphs and some basic ideas in special relativity.
Alternate Interior \(\small\measuredangle\)s
Euclid's proof of I.27 and some discussion about 'transitional' topics in math.
Proof using inscribed angles and AA similarity.
Formula for Intensity
The formula is related to simple division and graphed.
Euclid's proof of I.4 and some discussion about precision.
Inscribed \(\small\measuredangle\) Theorem
Proof involves 3 cases. Uses the base angle and exterior angle theorems.
Interactive demo and proof. Some notes about speculation in math.
Vertical \(\small\measuredangle\) Theorem
Proof of I.15 using I.13. Explains where vertical angles got their name.
Proof and discussion about intuition in mathematics.
Demo and explanation of the cissoid curve. Other stuff too.
Proof by contradiction of I.26. Some notes about how it was first used.
Interactive proportionality demo. Then the proof.