Exploring Proofs
The following are some activities and resources that you can use to start getting your hands wet in the world of solving proofs in Euclidean Geometry. Don't be afraid to get out there and explore books, journals, and the internet. The more you practice, the better you get at recognizing relationships, and building solid proofs.

Activity	Description
Pythagorean Theorem	This is a Geogebra activity exploring the proof of Pythagorean's Theorem. Try to solve it before looking at the answer.
Theorem of Convex Quadrilateral	This is a Geogebra applet exploring the theorem about convex quadrilaterals and their interior angles adding up to 360 degrees.
Euclid's Isosceles Postulate	Euclid's Isosceles Postulate states that the base angles of the Isosceles Triangle are equal to each other. Using the picture, try to construct the proof before looking at the answer.
Proof of Thales Theorem	This link takes you to another site that looks into the proof of Thales Theorem.
Basic Theorems of Euclidean Geometry	This is a document put togther with many of the basic theorems and proofs of Euclidean Geometry. It is a great to go through and get a good taste of what it takes to prove theorems.
Triangle Theorems	This is a site show proofs for the Side-Angle-Side, Angle-Side-Angle, etc. theorems of Euclidean Geometry.
Triangle Angle Theorems	This shows a proof of why the angles of a triangle add up to 180 degrees.

For teachers:
Below is an attach with a Activity Plan with worksheet for students to explore this website and the concepts of proofs and Euclidean Geometry.
      Worksheet