Curated OER
Logical Relationship of Postulates & Theorems
In this postulates and theorems instructional activity, students explore a concept map containing information about angles and sides, alternate interior angles, and diagonals of a parallelogram. They use the concept map to prove...
Curated OER
Properties of Geometry
In this properties of geometry activity, 10th graders solve and complete 12 different problems that include various theorems. First, they draw a figure that illustrates the SAS inequality property. Then, students prove that two line...
Illustrative Mathematics
Tangent to a Circle From a Point
Learners see application of construction techniques in a short but sophisticated problem. Combining the properties of inscribed triangles with tangent lines and radii makes a nice bridge between units, a way of using...
Curated OER
More Congruent Triangles
In this congruent triangles worksheet, 10th graders solve 5 various types of geometry problems related to triangles. First, they draw and label triangles, indicating the additional pairs of corresponding parts that would have to be...
Curated OER
Identify the Shape
10 this geometry worksheet, learners identify the different angles created by polygons and name the shape created based on the number of sides. There is an answer key.
Curated OER
Flying with Pythagoras
A lengthy narrative about Pythagoras and his students precedes an activity in which your young mathematicians practice using the Pythagorean theorem to solve three problems about flight and distance. Answers are provided.
Curated OER
Angles and Parallel Lines Homework
In this geometry worksheet, students identify the angles formed by parallel lines and a transversal. They differentiate between the angles of a transversal and that of a perpendicular line. There are 14 questions.
Curated OER
Crystals: Geometry and Groups
Students discuss the importance of examining crystals and experiment growing them. In groups, they complete a project in which they use groups in geometry just like crystallographers. They practice solving the groups and proofs and...
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...
Alabama Learning Exchange
Triangle Area: No Height? Use the Sine
No height? No problem! Learners use their knowledge and a little help from GeoGebra to develop the Law of Sines formula. The Law of Sines helps to determine the height of triangles to calculate the area.
EngageNY
Special Relationships Within Right Triangles—Dividing into Two Similar Sub-Triangles
Why are right triangles so special? Pupils begin their study of right triangles by examining similar right triangles. Verifying through proofs, scholars recognize the three similar right triangles formed by drawing the altitude. Once...
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
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
Why Doesn't SSA Work?
Students investigate the relationship between angles and their sides. In this geometry instructional activity, students prove why SSA does not work as a true angle side relationship theorem.
Curated OER
Inequalities and Triangles
Students prove and apply theorems of triangle inequality and hinge theorem. For 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
Challenge: Skills and Applications Lesson 3.4
In this geometry worksheet, students identify the missing angles formed by parallel lines and a transversal. They differentiate between parallel and perpendicular lines. There are four questions.
EngageNY
Review of the Assumptions (part 1)
What was the property again? Tired of hearing this from your pupils? Use this table to organize properties studied and as a reference tool for individuals. Learners apply each property in the third column of the table to ensure their...
Curated OER
Pythagorean Theorem by Graphic Manipulation
There are many different ways to show a proof of the Pythagorean Theorem. Here is a nice hands-on paper cutting activity that shows a graphic representation. You can even challenge your young Pythagoreans to come up with their own...
Curated OER
Watch It Slide!
Students work together to examine inclined planes. They create a plan to raise rocks to build pyramids. They discover the changes that occur when the angle is increased or decreased.
Curated OER
Triangle worksheets
In this geometry worksheet, 10th graders explore triangle properties, including the sum of the measures of the angles of a triangle, the triangle inequalities, properties of isosceles triangles, properties of congruent triangles, and...
Curated OER
Got Complements? with Cabri Jr.
Learners use the axes and measure angle tool to explore and calculate complementary angles with Cabri Jr. They also identify what happens to the calculation as they drag the endpoint into a different quadrant. Finally, they label each...
Curated OER
Congruent Triangles
In this congruent triangles worksheet, 10th graders solve and complete 10 different problems that include various forms of triangles. First, they name the method for proving each set of triangles congruent using the given information....
Curated OER
If-Then Statements and Postulates
In this if-then statements and postulates learning exercise, 10th graders solve 6 different problems related to if-then statements and postulates in geometry. First, they identify the hypothesis and conclusion of each conditional...
EngageNY
Prove the Pythagorean Theorem Using Similarity
Amaze your classes with the ability to find side lengths of triangles immediately — they'll all want to know your trick! Learners use the Pythagorean Theorem and special right triangle relationships to find missing side lengths.