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.
Flipped Math
Side Splitter Theorem
Apply perspective to similarity. Individuals learn about the Side Splitter Theorem by looking at perspective drawings. Pupils use the theorem and its corollary to find missing lengths in figures. Next, they practice using the theorem and...
EngageNY
Similarity and the Angle Bisector Theorem
Identifying and verifying reproducible patterns in mathematics is an essential skill. Mathematicians identify the relationship of sides when an angle is bisected in a triangle. Once the pupils determine the relationship, they prove it to...
EngageNY
Families of Parallel Lines and the Circumference of the Earth
How do you fit a tape measure around the Earth? No need if you know a little geometry! Pupils begin by extending their understanding of the Side Splitter Theorem to a transversal cut by parallel lines. Once they identify the proportional...
Inside Mathematics
Hopewell Geometry
The Hopewell people of the central Ohio Valley used right triangles in the construction of earthworks. Pupils use the Pythagorean Theorem to determine missing dimensions of right triangles used by the Hopewell people. The assessment task...
Curated OER
Mean Twisters - Mean Proportional
In this mean proportional activity, learners work in pairs to solve right triangle problems. They use ratios and proportions of similar triangles to determine a missing length. This two-page activity contains 16 problems.
Curated OER
Pythagorean Theorem
Students solve problems using the Pythagorean Theorem. For this geometry lesson, students identify different parts of a right triangle. They use the Pythagorean Theorem to calculate missing angles and sides.
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.,...
EngageNY
Comparing the Ratio Method with the Parallel Method
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,...
Curated OER
Parallel Lines and Proportional Parts
In this parallel lines and proportional parts worksheet, 10th graders solve 6 problems that include applying the theorems involved in proportional parts of triangles. First, they identify and describe each theorem. Then, students find...
Curated OER
Proportional Parts Homework
In this geometry worksheet, students differentiate between similarity and proportion. They use scale factor as they solve for the different proportions. There are 15 questions.
Curated OER
Modeling a Planetary Nebula
For this modeling a planetary nebula worksheet, students use a diagram to calculate the intensity at different radii from the center of the nebula. Students use the Pythagorean Theorem to determine the distance between two points on the...
EngageNY
The Angle-Angle (AA) Criterion for Two Triangles to Be Similar
What do you need to prove triangles are similar? Learners answer this question through a construction exploration. Once they establish the criteria, they use the congruence and proportionality properties of similar objects to find...
Curated OER
Using Proportions Self Check Quiz
In this geometry worksheet, students identify the different ratios of triangles using the theorems. They use SSS, SAS, ASAÂ and AAS to differentiate between triangles. There are 7 questions with an answer key.
Mathematics Vision Project
Similarity and Right Triangle Trigonometry
Starting with similar triangles and dilation factors, this unit quickly and thoroughly progresses into the world of right triangle features and trigonometric relationships. Presented in easy-to-attack modules with copious application...
Mathematics Vision Project
Module 5: Circles A Geometric Perspective
Circles, circles, everywhere! Pupils learn all about circles, central angles, inscribed angles, circle theorems, arc length, area of sectors, and radian measure using a set of 12 lessons. They then discover volume formulas through...
Curated OER
Geometric Proofs
For this geometric proof worksheet, students use geometric theorems and rules to prove given statements. They prove that given lines and angles are similar. This five-page worksheet contains ten 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...
Curated OER
Task: Grain Storage
Farming is full of mathematics, and it provides numerous real-world examples for young mathematicians to study. Here, we look at a cylinder-shaped storage silo that has one flat side. Given certain dimensions, students need to determine...
Curated OER
The Diagonal Of A Box
Young scholars solve problems using the pythagorean theorem. They use critical thinking skills in order to use a systematic process to solve the problem. Upon solving each problem the uniqueness of the lesson is asking students to give...
Curated OER
Side Splitter Triangles
Students investigate the side splitter theorem. For this geometry lesson, students estimate and solve problems dealing with ratios and proportions. They identify angles created by lines that are parallel.
Curated OER
Similarity and Congruence
Students explore the concept of similarity and congruence. In this similarity and congruence activity, students identify and verify whether or not two figures are similar, congruent, or neither. Students use postulates and theorems such...
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...
EngageNY
Searching a Region in the Plane
Programming a robot is a mathematical task! The activity asks learners to examine the process of programming a robot to vacuum a room. They use a coordinate plane to model the room, write equations to represent movement, determine the...