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.
Curated OER
Easy Worksheet: Counterexamples
In this counterexamples worksheet, high schoolers solve 10 short answer problems. Students prove the given statements false by providing a counterexample thus disproving the statement.
EngageNY
The Converse of the Pythagorean Theorem
Is it a right triangle or not? Introduce scholars to the converse of the Pythagorean Theorem with a lesson that also provides a proof by contradiction of the converse. Pupils use the converse to determine whether triangles with given...
Inside Mathematics
Quadrilaterals
What figure is formed by connecting the midpoints of the sides of a quadrilateral? The geometry assessment task has class members work through the process of determining the figure inscribed in a quadrilateral. Pupils use geometric...
Curated OER
Write the Counterexample
In this counterexample worksheet, students provide counterexamples for the four given statements. The solutions are not provided.
Curated OER
Inductive Reasoning and Conjecturing
In this inductive reasoning and conjecturing worksheet, 10th graders solve 4 problems that include applying inductive reasoning and conjecturing to each problem. First, they determine if each conjecture is true or false based on the...
Curated OER
Divisibility Rules
In this divisibility rules worksheet, students solve 18 different problems that include applying the divisibility rules to each. First, they identify the hypothesis and conclusion in logical deduction. Then, students determine the...
Curated OER
Inequalities and Triangles
Students prove and apply theorems of triangle inequality and hinge theorem. In this geometry lesson, students will discuss which triangle is bigger and why. They will use theorems, such as Exterior Angle Inequality or the Pythagorean...
Curated OER
Geometry Concepts and Applications
In this concepts and applications review activity, 10th graders solve and complete 40 various types of multiple choice problems. First, they write the equation of a vertical line passing through a point. Then, students find the...
Curated OER
If-Then Statements and Postulates
In this if-then statements and postulates instructional activity, 10th graders solve 16 various types of geometry problems that include identifying the hypothesis and conclusions of each conditional statement. Then, they write each...
Inside Mathematics
Rhombuses
Just what does it take to show two rhombuses are similar? The assessment task asks pupils to develop an argument to show that given quadrilaterals are rhombuses. Class members also use their knowledge of similar triangles to show two...
Curated OER
Investigating AAS
Students investigate the theorems of ASA, AAS, AAA and ASA. In this geometry lesson, students discuss the theorems of triangles and how it is used to solve for missing sides or angles. They review how two angles are formed by two rays...
Curated OER
Challenge: Skills and Applications Lesson 1.3
In this skills worksheet, students explain the Segment Addition Postulate, provide examples and counter examples and determine congruent line segments. This one-page worksheet contains 11 multi-step problems.
Virginia Department of Education
High School Mathematics Geometry Vocabulary Word Wall Cards
Having a good working knowledge of math vocabulary is especially important for geometry learners. Here are 119 pages worth of wonderfully constructed definitions, constructions, formulas, properties, theorems, and postulates. This is a...
EngageNY
Mid-Module Assessment Task - Geometry (Module 1)
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...
Virginia Department of Education
Similar Triangles
Pupils work in pairs to investigate what it takes to prove that two triangles are similar. They work through various shortcuts to find which are enough to show a similarity relationship between the triangles. Small groups work with the...
CK-12 Foundation
Ck 12: Ferromagnetic Material: Maximizing 4 Pizza Slices
[Free Registration/Login Required] Students explore the concept of conjectures and counterexamples by navigating through the interactive learning module and then answering questions that go along with the module. Students can also learn...