Virginia Department of Education
Lines and Angles
Explore angle relationships associated with transversals. Pupils construct parallel lines with a transversal and find the measures of the angles formed. They figure out how the different angles are related before constructing...
Illustrative Mathematics
Joining Two Midpoints of Sides of a Triangle
Without ever using the actual term, this exercise has the learner develop the key properties of the midsegment of a triangle. This task leads the class to discover a proof of similar triangles using the properties of parallel lines cut...
Math by Design
Transformations – Reflections
Scholars use interactive resources to figure out how to mathematically draw a reflection of a geometric shape viewed in a mirror. To conclude the activity, class members are asked to deduce the result of multiple reflections across...
Virginia Department of Education
Angles, Arcs, and Segments in Circles
Investigate relationships between angles, arcs, and segments in circles. Pupils use geometry software to discover the relationships between angles, arcs, and segments associated with circles. Class members use similar triangles to...
EngageNY
Three-Dimensional Space
How do 2-D properties relate in 3-D? Lead the class in a discussion on how to draw and see relationships of lines and planes in three dimensions. The ability to see these relationships is critical to the further study of volume and other...
EngageNY
Complex Numbers and Transformations
Your learners combine their knowledge of real and imaginary numbers and matrices in an activity containing thirty lessons, two assessments (mid-module and end module), and their corresponding rubrics. Centered on complex numbers and...
EngageNY
Informal Proof of AA Criterion for Similarity
What does it take to show two triangles are similar? The 11th segment in a series of 16 introduces the AA Criterion for Similarity. A discussion provides an informal proof of the theorem. Exercises and problems require scholars to apply...
EngageNY
What Lies Behind “Same Shape”?
Develop a more precise definition of similar. The lesson begins with an informal definition of similar figures and develops the need to be more precise. The class learns about dilations and uses that knowledge to arrive at a mathematical...
Virginia Department of Education
Transformations
The coordinate plane is a popular place! Identify rotations, reflections, and dilations on the coordinate plane. Pupils work in small groups to match transformations of a figure with the description of the transformation. They perform...
Virginia Department of Education
Distance and Midpoint Formulas
Small groups work through two guided activities to derive the distance and midpoint formulas for the coordinate plane. The activities begin with concrete examples and move to abstract.
National Wildlife Federation
What is DBH?
When measuring the circumference of a tree, does it matter how high you place the measuring tape? Most scholars have never considered this question, but scientists know that measurement techniques must be standardized. The 13th lesson in...
EngageNY
Four Interesting Transformations of Functions (Part 1)
Understanding how functions transform is a key concept in mathematics. This introductory lesson makes a strong connection between the function, table, and graph when exploring transformations. While the resource uses absolute value...
National Security Agency
What’s Your Coordinate?
Your middle schoolers will show what they know with their bodies when they become the coordinate plane in this conceptual development unit. Starting with the characteristics of the coordinate plane, learners develop their skills by...
EngageNY
Similarity
Use the coordinate plane to show two figures are similar. The lesson incorporates congruence transformations and dilations to move a figure on to another figure. Pupils determine that if a similarity transformation exists between two...
Shodor Education Foundation
An Introduction To Quadrilaterals
Young geometers investigate and apply properties of quadrilaterals. After a review and discussion of key terms, students use a computer applet to explore four-sided figures and classify them according to their attributes. The...
Mathematics Assessment Project
Identifying Similar Triangles
Math whizzes work with angle sums and exterior angles to figure out the measure of other angles. This particular publication provides comprehensive support in the form of an anticipatory activity, questions designed to prompt discussion,...
Education Development Center
Proof with Parallelogram Vertices
Geometric figures are perfect to use for proofs. Scholars prove conjectures about whether given points lie on a triangle and about midpoints. They use a provided dialogue among fictional learners to frame their responses.
Virginia Department of Education
Arc Length and Area of a Sector
What do skateboarding and baked goods have in common with math? You can use them to connect half-pipe ramps and cakes to arcs and sectors. Pupils compare the lengths of three different ramp options of a skate park. They calculate the...
Alabama Learning Exchange
Pennies, Pennies and More Pennies
Learners determine the number of pennies needed to fill a room. In this pennies lesson plan, students work in groups to determine the number of pennies needed to fill a room. They compute the probability of the head of a pin landing on...