EngageNY
Dividing Segments Proportionately
Fractions, ratios, and proportions: what do they have to do with segments? Scholars discover the midpoint formula through coordinate geometry. Next, they expand on the formula to apply it to dividing the segment into different...
EngageNY
Unknown Angle Problems with Inscribed Angles in Circles
We know theorems about circles—now what? Class members prove a theorem, with half the class taking the case where a point is inside the circle and half the class taking the case where a point is outside the circle. The lesson plan then...
Curated OER
Geometry Lesson 7: Line Segments And Angles
Fourth graders examine and identify line segments and angles using dot paper to draw them. They look at vertical, horizontal, intersecting, parallel and perpendicular lines, draw right angles and angles that are greater than and less...
Curated OER
Escher-Esque Tessellations
Middle and high schoolers participate in a seven-part lesson plan creating Escher-Esque tessellations. They demonstrate their knowledge of geometric transformations after viewing a PowerPoint presentation, conducting Internet research,...
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
Motion Along a Line – Search Robots Again
We can mathematically model the path of a robot. Learners use parametric equations to find the location of a robot at a given time. They compare the paths of multiple robots looking for parallel and perpendicular relationships and...
EngageNY
Secant Angle Theorem, Exterior Case
It doesn't matter whether secant lines intersect inside or outside the circle, right? Scholars extend concepts from the previous instructional activity to investigate angles created by secant lines that intersect at a point exterior...
EngageNY
The Distance from a Point to a Line
What is the fastest way to get from point A to line l? A straight perpendicular line! Learners use what they have learned in the previous lessons in this series and develop a formula for finding the shortest distance from...
Illustrative Mathematics
Finding an Unknown Angle
Teach your class how to apply their knowledge of geometry as they explore the unknown. In order to find an unknown angle, learners must understand that rectangles have four interior right angles, that right angles have 90 degrees, and...
Mascil Project
Pottery
Don't cry over broken pottery. A cross-curricular lesson plan challenges pupils to consider how to restore ancient pottery. Using a computer program and their knowledge of transformations, they come up with a way to recreate the original...
Illustrative Mathematics
All vs. Only Some
All shapes have certain defining attributes that set them apart from others. In order to understand this, young mathematicians look at examples and non-examples of triangles, rectangles, and squares, working as a whole class to create...
Illustrative Mathematics
Grandfather Tang's Story
It's amazing the complex figures that can be made using only a few simple shapes. Following a class reading of the children's book Grandfather Tang's Story by Ann Tompert, young mathematicians use sets of tangrams to create models...
Illustrative Mathematics
3-D Shape Sort
From the apple on your desk and the coffee cup in your hand, to the cabinets along the classroom wall, basic three-dimensional shapes are found everywhere in the world around us. Introduce young mathematicians to the these common figures...
Illustrative Mathematics
Two Wheels and a Belt
Geometry gets an engineering treatment in an exercise involving a belt wrapped around two wheels of different dimensions. Along with the wheels, this belt problem connects concepts of right triangles, tangent lines, arc length, and...
Curated OER
Geometry, Measurement & Reasoning
Learners complete worksheets involving rotational symmetry. In this geometry lesson, students complete worksheets to identify rotational symmetry and rotations. They compare and contrast rotated figures. Learners examine the relationship...
Curated OER
Geometry, Measurement & Reasoning
Students construct two-column proofs. In this geometry lesson, students use deductive reasoning and geometric properties to justify given geometric statements. Students compare and contrast proofs.
Curated OER
Quilting Geometry
Study geometry through the concept of quilt design. High schoolers examine the geometric shapes in various quilts and then create their own quilts using geometric shapes that fit together. In the end, they write a paragraph to...
Curated OER
A Lesson on the Root Spiral
Students create lines and shapes with a compass and a straight edge. In this geometry activity, students investigate square roots, irrational numbers and spirals. They explore nature to see the shapes representing mathematics and...
Curated OER
Angles Lesson Plan
Students explore the relationship of angles as it relates to 2 and 3-D shapes. In this geometry lesson, students differentiate between acute, obtuse, right, alternate interior, exterior and adjacent angles. They manipulate a math...
Curated OER
Geometry, Pi, and Ancient Civilizations
By working together, pairs of learners will complete a Pi webquest. Using the internet, they examine the ways people in the Ancient Civilizations of Egypt, Babylonia and Greece used Pi. To end the lesson plan, they review the concepts of...
Curated OER
Angles - Unlocking Geometry
Students investigate the concept of angles and how they are used in geometry. They construct polygons using various types of angles and then classify them according to their physical properties. Students use a computer program in order...
Curated OER
Geometry Finding Pentominoes
Students explore the characteristics of geometric shapes. In this geometric shapes lesson, students use tiles to draw pentominoes. Students participate in various learning center activities focused on configuring pentominoes.
EngageNY
Perimeter and Area of Triangles in the Cartesian Plane
Pupils figure out how to be resourceful when tasked with finding the area of a triangle knowing nothing but its endpoints. Beginning by exploring and decomposing a triangle, learners find the perimeter and area of a triangle. They...
EngageNY
Segments That Meet at Right Angles
Can segments be considered perpendicular if they don't intersect? Learners look at nonintersecting segments on the coordinate plane and make conclusions about the lines that contain those segments. They determine if they are...