EngageNY
Reflections
Facilitate creativity in your math class as individuals learn the definition of a geometric reflection and correctly construct a model, as well as its reflected image. They use a perpendicular bisector and circles to elaborate on...
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...
EngageNY
Trigonometry and the Pythagorean Theorem
Ancient Egyptians sure knew their trigonometry! Pupils learn how the pyramid architects applied right triangle trigonometry. When comparing the Pythagorean theorem to the trigonometric ratios, they learn an important connection that...
EngageNY
Between-Figure and Within-Figure Ratios
Tie the unit together and see concepts click in your young mathematicians' minds. Scholars apply the properties of similar triangles to find heights of objects. They concentrate on the proportions built with known measures and solve to...
EngageNY
What Is Area?
What if I can no longer justify area by counting squares? Lead a class discussion to find the area of a rectangular region with irrational side lengths. The class continues on with the idea of lower approximations and...
EngageNY
General Pyramids and Cones and Their Cross-Sections
Are pyramids and cones similar in definition to prisms and cylinders? By examining the definitions, pupils determine that pyramids and cones are subsets of general cones. Working in groups, they continue to investigate the relationships...
EngageNY
Analytic Proofs of Theorems Previously Proved by Synthetic Means
Prove theorems through an analysis. Learners find the midpoint of each side of a triangle, draw the medians, and find the centroid. They then examine the location of the centroid on each median discovering there is a 1:2 relationship....
Curated OER
Patterns in Pascal's Triangle
Students examine the patterns in Pascal's Triangle. In this recognizing lesson, students view a model of Pascal's Triangle and describe the patterns of the multiples. Students identify the shapes that are made within Pascal's Triangle.
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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,...
EngageNY
Properties of Similarity Transformations
You can explain it, but can you do it? After learners view a sequence of transformations, the next logical step is creating the transformation. Challenge your classes to construct a composition of transformations and verify the...
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...
EngageNY
Using Trigonometry to Determine Area
What do you do when you don't think you have enough information? You look for another way to do the problem! Pupils combine what they know about finding the area of a triangle and trigonometry to determine triangle area when they don't...
EngageNY
Properties of Area
What properties does area possess? Solidify the area properties that pupils learned in previous years. Groups investigate the five properties using four problems, which then provide the basis for a class discussion.
EngageNY
Copy and Bisect an Angle
More constructions! In this third installment of a 36-part series, learners watch a YouTube video on creating door trim to see how to bisect an angle. They then investigate how to copy an angle by ordering a given list of steps.
EngageNY
Special Lines in Triangles (part 2)
Medians, midsegments, altitudes, oh my! Pupils study the properties of the median of a triangle, initially examining a proof utilizing midsegments to determine the length ratio of a median. They then use the information to find missing...
EngageNY
Triangle Congruency Proofs (part 2)
Looking to challenge your students that have mastered basic triangle congruence proofs? A collection of proofs employ previously learned definitions, theorems, and properties. Pupils draw on their past experiences with proofs to...
EngageNY
Why Stay with Whole Numbers?
Domain can be a tricky topic, especially when you relate it to context, but here is a lesson that provides concrete examples of discrete situations and those that are continuous. It also addresses where the input values should begin and...
Curated OER
Math in the Wetlands Field Trip
Get your class out in the environment for hands on math activities. For this wetlands lesson, learners transplant native plants, calculate how much soil is needed, and perform math activities based on this experience. They then make...
EngageNY
Representing, Naming, and Evaluating Functions (Part 1)
Begin the discussion of domain and range using something familiar. Before introducing numbers, the lesson uses words to explore the idea of input and outputs and addresses the concept of a function along with domain and range.
EngageNY
Distance on the Coordinate Plane
Apply the Pythagorean Theorem to coordinate geometry. Learners find the distance between two points on a coordinate plane by using the Pythagorean Theorem. The vertical and horizontal change creates a right triangle, which allows...
Ohio Department of Education
Describing and Creating Plane Figures - Grade One
Young mathematicians draw, create, and describe different shapes using triangles. They discuss attributes of the original and created shapes. Pupils classify the created shapes and draw and write in mathematics journals to communicate...
Curated OER
Compound Inequalities and Graphing
Put geometry skills to the test! Learners solve compound inequalities and then graph the inequalities on a coordinate plane using their geometric skills. They identify the slope and y-intercept in order to graph correctly. I like this...
EngageNY
The Geometric Effect of Some Complex Arithmetic 2
The 10th instructional activity in a series of 32, continues with the geometry of arithmetic of complex numbers focusing on multiplication. Class members find the effects of multiplying a complex number by a real number, an imaginary...
EngageNY
Representing Reflections with Transformations
In the 16th lesson in the series of 32 the class uses the concept of complex multiplication to build a transformation in order to reflect across a given line in the complex plane. The lesson breaks the process of reflecting across a line...