Geometric Proof Teacher Resources

This visual, manipulative-based format for teaching geometric proofs nicely scafolds learners' development of mathematical reasoning and proof skills. This sample represents a proof of the congruence of vertical angles in four formats;...

Stuck trying to remember the formal language of a geometric proof? Never fear, this handout has them all ready to go. The reasons are sectioned by topic so this handy guide is ready when you are to tackle those two column proofs. 

Order in the court! Turn your geometry classroom into a courtroom and have your pupils defend their proofs. A fun and educational lesson allows both individual and group work with geometric proofs and group presentations in a court of...

In this geometry worksheet, learners take the derivative of functions. They prove theorems using geometric proofs. There are 13 questions.

Completing the square is not just an algebraic manipulation. The interactive contains a geometric proof of the concept of completing the square in algebra. The proof uses the area model of multiplication to build a square from the terms...

Cut straight to the proof. Given cutouts of different quadrilaterals, pupils draw diagonals. Learners cut up the figures along the diagonals to see whether they bisect each other. Scholars develop a geometric proof for the property they...

Proving triangles are similar is often an exercise in applying one of the many theorems young geometers memorize, like the AA similarity criteria. But proving that the criteria themselves are valid from basic principles is a great...

Are you looking for a comprehensive review that addresses the Common Core standards for geometry? This is it! Instruction and practice problems built specifically for standards are included. The material includes geometry topics from...

What do congruent triangles have to do with diagonals of a rhombus? Given a rhombus, pupils develop a proof showing that a diagonal bisects opposite angles. The learners use what they know about congruent triangles to create the...

Isosceles means two sides are congruent. Given an isosceles triangles, pupils develop a geometric proof showing that the two base angles are congruent. 

Here is a worksheet that lines up perfectly with the skills needed to finish a geometric proof. Eleven problems are given to see if learners can prove that lines are parallel or angles are congruent. 

Students examine their prior knowledge of algebra to explore geometric proof. In this proving supplementary and complementary lesson, students prove a solution to an equation using algebraic properties. Students then write their own...

Geometric figures are perfect to use for proofs. Scholars prove conjectures about whether given points lie on a triangle and about midpoints. They use a provided dialogue among fictional learners to frame their responses.

In this geometric proof worksheet, students use geometric theorems and rules to prove given statements. They prove that given lines and angles are similar. This five-page worksheet contains ten problems.

Delving into a proof that the diagonals of a rhombus are perpendicular to each other, this lecture evaluates the angles and sides of this figure. It would serve as a great test preparation activity.

After addressing the terminology used with medians and centroids of triangles in the first part of this series, the instructor shows how to solve this type of problem. He illustrates the concepts by using a high-level problem....

The terminology used in geometry, including such words as centroid and median are discussed in this video. Through this lecture, young mathematicians can see a visual representation both median and centroid. Also, a proof showing how to...

The terminology used in geometry, including such words as centroid and median are discussed in this video. Through this lecture, young mathematicians can see a visual representation both median and centroid. Also, a proof showing how to...

Finding the area of each of the triangles that are created by drawing two diagonal lines through a rectangle is explored in this lecture. It provides a detailed explanation of how to use a formula to solve the given problem. Tip: Use...

Delving into basic trigonometry, this resource shows how to find the area of an inscribed equilateral triangle. Using a high-level problem, HeronÕs theorem is used to find the area of a figure. Prior to SAT testing, use this as a review.

Honing in on the technique necessary to find the area of a rhombus, Sal describes how to accomplish this goal using the circumradii of triangles. He shows how to use the radii of circles circumscribed around triangles to find the area....

Finding the area of each of the triangles that are created by drawing two diagonal lines through a rectangle is explored in this lecture. It provides a detailed explanation of how to use a formula to solve the given problem. Tip: Use...

Delving into basic trigonometry, this resource shows how to find the area of an inscribed equilateral triangle. Using a high-level problem, HeronÕs theorem is used to find the area of a figure. Prior to SAT testing, use this as a review.

In this geometry worksheet, 10th graders supply the missing step or justification of a step in two column geometric proof.  The one page interactive worksheet contains five multiple choice questions and is self checking.