Geometry theorems

Free circle theorems GCSE maths revision guide, including step by step examples, exam questions and free worksheet.

Keep this Cheat Sheet handy as you're working on geometry. It includes formulas, theorems, proof strategies, common symbols, and more.

This is an awesome resource to help your students stay organized and learn all the different postulates and theorems they will use while learning how to do two column proofs in geometry. Check it out! I have powerpoint lessons to go along with it as well!

I taught Segments in Triangles as a mini-unit this year. I spent one day on midesgments and two days on altitudes, angle bisectors, perpendicular bisectors, and medians. Then, I spent one day on the Triangle Inequality Theorem. Then, review and test. I used this flip book for all of the segments in triangles. I used a powerpoint (which is unusual for me) to go through the vocabulary and examples. It worked well in class and it was nice to not have to write so much while the students were…

Ten geometry theorem proofs you need to teach in your geometry class. Read the list and then find some new ways to teach geometry theorems ...

I've taught Angle Sum Theorem in the past but I felt as though my students didn't truly understand what it means or how it actually works. They can tell you that all angles in a triangle add up to 180 degrees, but if you ask them how do you know it's true they couldn't give you a good reason. I usually get the response of "because you told us it does". UGH! Not the response I'm looking for. This year I was determined to find a way that would help them understand just how it worked, and I…

The Pythagorean Theorem If we have a right triangle, and we construct squares using the edges or sides of the right triangle (gray triangle in the middle), the area of the largest square built on the hypotenuse (the longest side) is equal to the sum of the areas of the squares built on the other...

Are you looking for some real world practice to teach the Pythagorean Theorem? This set of Pythagorean Theorem practice is a great way to help kids see its importance and relevance in life. Kids do well with math problems that they can relate to, or at least ones that would make sense in their worldviews. This post shares some understanding of what it means and how to apply it to solve problems.

I got frustrated. I was teaching triangle congruence in my high school geometry class and didn't have a way to have the five theorems we were discussing in ONE easy to see place. So, I made one! This reference sheet allows students to easily see the different methods of proving triangles congruent in one place. And, to make it even better, I created a quick coloring page to be copied side by side with it to give them immediate practice and even more visuals! I've discovered, with Geomet...