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...
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...
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...
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...
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
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.
Illustrative Mathematics
Why Does SSS Work?
While it may seem incredibly obvious to the geometry student that congruent sides make congruent triangles, the proving of this by definition actually takes a bit of work. This exercise steps the class through this kind of proof by...
Illustrative Mathematics
Joining Two Midpoints of Sides of a Triangle
Without ever using the actual term, this exercise has the learner develop the key properties of the midsegment of a triangle. This task leads the class to discover a proof of similar triangles using the properties of parallel lines cut...
Learning to Live
Attributes of a Civil Society
What makes a society civil? High school freshmen search for examples of justice, kindness, peace, and tolerance in news media and brainstorm how they can promote these attributes in their schools, communities, and world. The well-rounded...
Curated OER
Making a Two - Colorable Map
Pupils make a two - colorable map by following directions given to them. In this map lesson plan, students follow 5 sets of directions and discuss their activity.
EngageNY
End-of-Module Assessment Task - Geometry (module 1)
Have you hit a wall when trying to create performance task questions? Several open-ended response questions require a deep level of thinking. Topics include triangle congruence, quadrilaterals, special segments, constructions, and...
Virginia Department of Education
Pythagorean Theorem
Investigate the meaning of the Pythagorean Theorem through modeling. After comparing the area of the square of each side, individuals cut triangles and squares to facilitate the comparison.
Curated OER
Quilt Patch Proof
Students construct a convincing argument that the same amount of fabric is needed for each color of quilt being made in a specific design. They justify the relationship between vertical angles and the sum of the interior angles. Students
Curated OER
Reflections and Equilateral Triangles
Your learners collaboratively find the lines of symmetry in an equilateral triangle using rigid transformations and symmetry. Through congruence proofs they show that they understand congruence in terms of rigid motions as they prove...
Curated OER
Comprehension Strategies: Drawing Inferences
The proof is in the details! A richly detailed plan provides clear examples of how to draw inferences from text and how to provide support drawn directly from the text.
Science Matters
Earthquake Building/Shaking Contest
Japan is one of only a handful of countries that constructs buildings that are almost earthquake proof. The 13th lesson in the 20-part series challenges scholars to build structures to test against earthquakes. With limited materials and...
Curated OER
Getting it Right! An Investigation of the Pythagorean Theorem
In order to learn about the Pythagorean Theorem, young mathematicians investigate relations and patterns between different sides of a right triangle to look for possible relations among the squared sides. Once they have established the...
Curated OER
Keyboarding: Formatting A Report Using MLA Style
Introduce your class to the MLA style of formatting. In addition to studying the formatting, learners improve language skills and review word processor features. They use the Interwrite SchoolPad for the first time to assist in proofing...
Curated OER
The Right Stuff
Studentsare introduced to the Pythagorean Theorem by exploring right triangles and the squares built on each side. They apply the Pythagorean Theorem to real-world problems. Students u se informal and nonformal arguments of proof (i.e.,...
Curated OER
Interactivate - Lines, Rays, Line Segments, and Planes
Students explore lines, rays, line segments, and planes. In this math lesson, students discuss the math concepts and direct their instructor in graphing functions. Students collaborate in graphing additional functions.
Curated OER
El Nino Lesson
Students compare graphs of weather occurrences. In this environmental lesson plan, students will being using the website to gather weather related information for a certain time period. The students will then graph the data that will be...