Curated OER
Euclidean Direct Proofs
Learning how to prove theorems in geometry can be challenging. This resource explains what a proof is, and the different styles for proofs. It also contains links to web-based practice problems that help guide learners though example...
Mathed Up!
Proof
Scholars learn how to write number theory proofs by viewing a video reviewing techniques for proofs on divisibility, parity, and consecutive integers. They then write proofs for a handful of conjectures on a worksheet.
EngageNY
Informal Proofs of Properties of Dilations
Challenge the class to prove that the dilation properties always hold. The lesson develops an informal proof of the properties of dilations through a discussion. Two of the proofs are verified with each class member performing the...
Curated OER
Proof of the Pythagorean Theorem Using Transformations
Middle and high schoolers construct a triangle using Cabri Jr. They construct squares on each of the legs and hypotenuse of the triangle. Pupils show that the area of the squares on the leg equal the area of the square on the hypotenuse.
Curated OER
Indirect Proof and Inequalities in one Triangle
In this geometry worksheet, 10th graders complete an indirect proof and order the sides or angles of a triangle. Also, students determine if a triangle can have sides with the given lengths. The two page worksheet contains twelve...
Mathematics Vision Project
Geometric 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...
Shmoop
Coordinate Proofs
How do you know you know? Prove it! The guide goes through several examples and includes a link to a video to teach learners how to work through coordinate proofs. The goal is to prove that different shapes are indeed that shape.
GeoGebra
Conjectures and Proof
Transform proofs using triangle rotations. By rotating a triangle around various points, class members develop proofs. Participants prove relationships of alternative interior angles formed by parallel lines and the sum of the interior...
Illustrative Mathematics
Right Triangles Inscribed in Circles I
One of the basic properties of inscribed angles gets a triangle proof treatment in a short but detailed exercise. Leading directions take the learner through identifying characteristics of a circle and how they relate to angles and...
Curated OER
Why do Stars Rise in the East?
In this stars rise in the east worksheet, students use geometry to show how the Earth rotates from west to east and why celestial bodies appear to rise in the east and set in the west. Students draw a figure and label given points in...
Curated OER
Direct Object Pronouns
In this direct object pronouns instructional activity, students read sentences and identify direct objects, then change the direct objects to pronouns. Students determine seventeen answers.
Illustrative Mathematics
Shortest Line Segment from a Point P to a Line L
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 class...
Georgia Department of Education
Analytic Geometry Study Guide
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...
Illustrative Mathematics
Equal Area Triangles on the Same Base II
A deceptively simple question setup leads to a number of attack methods and a surprisingly sophisticated solution set in this open-ended problem. Young geometers of different strengths can go about defining the solutions graphically,...
Curated OER
From Hypothesis to Conclusion...Reading Maps to Understand Proofs
Tenth graders explore the concept of proof. In this proof lesson, 10th graders work in groups to collectively write proofs for directions to places on a map. Students give directions to specific places in big cities such as from the New...
Curated OER
Pre-Proof Warm-Ups
For this pre-proofs worksheet, 10th graders solve and complete 10 different problems that include various proofs and their definitions. They use the diagram shown and the given information to write the direct conclusion for each case....
Curated OER
Proofs
In this proofs learning exercise, 10th graders solve and graph 8 different equations. First, they prove that each triangle is either congruent or similar. Then, students use the concept of corresponding parts of congruent triangles to...
Curated OER
Direct Object Pronouns
In this direct object pronouns practice worksheet, students identify direct objects in 10 sentences and rewrite 7 of the 10 sentences by replacing the direct objects with pronouns.
Mathematics Vision Project
Module 6: Congruence, Construction, and Proof
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 unit...
West Contra Costa Unified School District
Derivation of the Quadratic Formula
What connection does the quadratic formula have with a quadratic equation? Using a matching activity, pupils construct the algebraic derivation of the quadratic formula in this Algebra II lesson task. The task provides two variations of...
Curated OER
Quiz: Direct Euclidean Proofs
In this Euclidean proof learning exercise, students observe models and read given proofs. Students determine conclusions based upon the given information. This one-page learning exercise contains ten Euclidean proof problems.
Curated OER
Two Column Logic Proofs
Young scholars complete two column proofs. In this geometry activity,students derive the reasons their answers are correct using logic. They write the proof step by step using two columns.
Calvin Crest Outdoor School
Survival
Equip young campers with important survival knowledge with a set of engaging lessons. Teammates work together to complete three outdoor activities, which include building a shelter, starting a campfire, and finding directions in the...
Chapman University
Derivative of sin x
Direct and to the point (the slope at a point that is) describes this one-page proof of the derivative of the sin(x). The definition of a derivative using a limit is the first step in this sequential, algebraic, explanation of how the...