Curated OER
Transformations in the Coordinate Plane
Your learners connect the new concepts of transformations in the coordinate plane to their previous knowledge using the solid vocabulary development in this unit. Like a foreign language, mathematics has its own set of vocabulary terms...
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
Tile Patterns I: Octagons and Squares
This can be used as a critical thinking exercise in congruence or as a teaching tool when first introducing the concept. Four octagons are arranged in such a way that a square is formed in the middle. With this information, geometry...
Curated OER
Similar Figures
In this similar figures worksheet, students identify corresponding sides and corresponding angles of given polygons. They identify similar figures. This three-page worksheet contains 18 problems.
Willow Tree
Ratios and Proportions with Congruent and Similar Polygons
Investigate how similar and congruent figures compare. Learners understand congruent figures have congruent sides and angles, but similar figures only have congruent angles — their sides are proportional. After learning the...
Houghton Mifflin Harcourt
Unit 5 Math Vocabulary Cards (Grade 6)
Acute angle, line of symmetry, and vertex are a few terms you'll find in a set of 90 flashcards designed to reinforce math vocabulary. Included in the set are two types of cards; a word card printed in bold font, and a...
EngageNY
Properties of Parallelograms
Everyone knows that opposite sides of a parallelogram are congruent, but can you prove it? Challenge pupils to use triangle congruence to prove properties of quadrilaterals. Learners complete formal two-column proofs before moving on to...
Virginia Department of Education
How Many Triangles?
Something for young mathematicians to remember: the sum of any two sides must be greater than the third. Class members investigates the Triangle Inequality Theorem to find the relationship between the sides of a triangle. At the...
Curated OER
Angles and Similarity
High schoolers identify triangles as similar or congruent. In this geometry lesson, students drag triangles around on the navigator to see the effect of different angles on the shape of the triangle. They discuss angle similarity and...
Curated OER
Corresponding Parts of Similar Triangles
Here is a lesson that has learners take a look at corresponding parts of similar triangles, ratios of similarity, reductions and enlargements. They'll manipulate the scale factor (r) to observe the changes in similar triangles and then...
Curated OER
Exploring Characteristics Needed to Prove Two Trianlges Congruent
Tenth graders explore congruent triangles. In this geometry lesson, 10th graders investigate the conditions necessary to prove two triangles congruent. The lesson combines dry erase board activities and the use of technology.
Curated OER
Measurement of Angles
Students measure angles that are formed by parallel lines and a transversal lines. For this angles lesson plan, students measure and define angles that are made by parallel and transversal lines. They will color code the angles based on...
Curated OER
Parallel Lines and Types of Angles
In this angles and parallel lines instructional activity, students solve 40 problems that pertain to parallel lines, supplementary, vertical, corresponding and alternate angles. There is instruction on the page with examples. This page...
Curated OER
Measurement of a Central Angle
Students calculate the measurement of a central angle. For this geometry lesson, students identify properties of circles. They use Cabri software to create and analyze graphs.
Curated OER
Why Does ASA Work?
Your geometry learners explore Angle-Side-Angle congruence in this collaborative task. The sum of the interior angles of all triangles being one hundred eighty degrees, is the key learners will discover as they explain their reasoning...
Curated OER
Proportional Segments Between Parallel Lines
Students identify similar triangles. In this proportional segments instructional activity, students identify corresponding sides, set up ratios, and find the length of the missing side of a triangle. They use the...
Curated OER
Exploring Similar Polygons
In this exploring similar polygons worksheet, 10th graders solve 9 various types of problems related to determining whether each polygon is similar or not. First, they write 3 equal ratios to show corresponding sides are proportional to...
Curated OER
Searching for Angles and Lines
Middle schoolers work to find and reinforce concepts related to lines and angles. They identify the characteristics of shapes that have one, two, and three dimensions. The students also work on definitions related to the geometry of shapes.
Illustrative Mathematics
Midpoints of the Sides of a Paralellogram
This task asks learners to prove that the segment joining the midpoints of two sides of a parallelogram is both congruent and parallel to an adjacent side of the parallelogram. The activity would be good to use in a discussion about how...
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
Indirect Measurement with Similar Triangles
Students use similar triangles to find missing heights. In this using similar triangles to find missing heights lesson plan, students use proportions to find the heights of missing side lengths. Students find the height of...
Curated OER
Identifying Similar Triangles
In this identifying similar triangles worksheet, 10th graders solve 6 different types of problem that include identifying and comparing similar triangles. First, they identify the three ways that determine whether two triangles are...
Curated OER
Exploring Similar Polygons
In this exploring similar polygons worksheet, 10th graders solve 9 various problems that are related to similar polygons. First, they define similar and the symbol used to identify similar to another. Then, students find the measurement...
Curated OER
Arc Measurement Based on The Measurement of a Central Angle
Students define keywords that are important to solve problems. In this geometry lesson, students find the arc length and angle of a circle. They convert between radians and degrees.