Looking to challenge your students that have mastered basic triangle congruence proofs? A collection of proofs employ previously learned definitions, theorems, and properties. Pupils draw on their past experiences with proofs to...

Proofs are usually an intimidating assignment. An engaging lesson focused on geometric proofs may reduce the anxiety! Pupils choose between several triangle proofs to complete and work on completing them. The...

This amazingly extensive unit covers a wealth of geometric ground, ranging from constructions to angle properties, triangle theorems, rigid transformations, and fundamentals of formal proofs.  Each of the almost-forty lessons...

Can they put it all together? Ninth graders apply what they know about proofs and triangle congruence to complete these proofs. These proofs go beyond the basic triangle congruence proofs and use various properties, theorems, and...

Prove the Pythagorean Theorem using multiple informal proofs. Scholars first develop an understanding of the origins of the Pythagorean Theorem through proofs. They round out the activity by using the theorem to find missing side lengths...

Trace the links between a variety of math concepts in this far-reaching unit. Ideas that seem very different on the outset (like the distance formula and rigid transformations) come together in very natural and logical ways. This...

Can you prove it? Lead your class through the development of the Side Splitter Theorem through proofs. Individuals connect the ratio and parallel method of dilation through an exploration of two proofs. After completing the proofs,...

Construct yourself a winning geometry unit. A set of lessons introduces geometry scholars to constructions and proofs with compasses and straightedges. It also covers triangle congruence through transformations. This is the second of...

What does it take to show two triangles are similar? The 11th segment in a series of 16 introduces the AA Criterion for Similarity. A discussion provides an informal proof of the theorem. Exercises and problems require scholars to apply...

One of the hardest skills for many young geometers to grasp is to move beyond just declaring obvious things true, and really returning to fundamental principles for proof. This brief exercise stretches those proving muscles as the...

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 does similarity have to do with the Pythagorean Theorem? The activity steps through the proof of the Pythagorean Theorem by using similar triangles. Next, the teacher leads a discussion of the proof and follows it by an animated...

Scholars determine distances on the coordinate plane to find areas. The instructional activity begins with a proof of the formula for the area of a parallelogram using the coordinate plane. Pupils use the coordinate plane to determine...

Your class may believe that geometry is a trial, but they don't know how right they are. A thorough math lesson combines the laws of logic with the laws of geometry. As high schoolers review the work of historical mathematicians and...

The Pythagorean Theorem makes an appearance yet again in this lesson on polynomial identities. Learners prove a method for finding Pythagorean triples by applying the difference of squares identity. 

Pupils complete a review worksheet that highlights the key problems from the first eight lessons in the series. Topics include the Pythagorean Theorem and its converse, as well as finding volume of three-dimensional figures.

Logical thinking is at the forefront of this jam-packed lesson, with young mathematicians not only investigating geometric concepts but also how they "know what they know". Through each activity and worksheet, learners wrestle with...

Prove theorems through an analysis. Learners find the midpoint of each side of a triangle, draw the medians, and find the centroid. They then examine the location of the centroid on each median discovering there is a 1:2 relationship....

How do you prepare class members for the analytical thinking they will need in the real world? An assessment requires the higher order thinking they need to be successful. The module focuses on the concept of rigid transformations...

Extend young mathematicians' understanding of area with a geometry lesson on trapezoids. Building on their prior knowledge of rectangles and triangles, students learn how to calculate the area of trapezoids and other...

Make the connection between the distance formula and the equation of a circle. The teacher presents a lesson on how to use the distance formula to derive the equation of the circle. Pupils transform circles on the coordinate plane and...

How do you solve for an unknown angle? In this sixth installment of a 36-part series, young mathematicians use concepts learned in middle school geometry to set up and solve linear equations to find angle measures.

Everyone knows that opposite sides of a parallelogram are congruent, but can you prove it? Challenge pupils to use triangle congruence to prove properties of quadrilaterals. Learners complete formal two-column proofs before moving on to...

Can you prove it? Making assumptions in geometry is commonplace. This resource requires mathematicians to prove the parallel line postulate through constructions. Learners construct parallel lines with a 180-degree rotation and then...