Government of Hong Kong
Areas and Volumes - 2D Shapes
Unfortunately for young mathematicians, the world isn't made entirely of parallelograms, triangles, and trapezoids. After first learning the area formulas for these common shapes, young scholars apply this new knowledge to...
Arizona Department of Education
Area and Perimeter of Regular and Irregular Polygons
Extend young mathematicians' understanding of area with a geometry lesson on trapezoids. Building on their prior knowledge of rectangles and triangles, students learn how to calculate the area of trapezoids and other...
PreKinders
A World of Shapes
There are shapes everywhere you see! Use a presentation about shapes to encourage young learners to find squares, circles, triangles, and rectangles in a series of pictures. One slide shows kids what the shapes look like, and then a...
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
Alike or Different Game
How are a circle and triangle alike? How are they different? These are the types of questions children will answer while playing this fun geometry game. Including a variety of conventional and unconventional shapes, this activity allows...
Scholastic
Study Jams! Area of a Triangle
Even though there is a wide variety of different triangles in the world, knowing a single equation allows us to find the area of each and every one of them. Follow along with this step-by-step presentation as Zoe clearly models how to...
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...
Curated OER
Finding the Area of an Equilateral Triangle
The problem seems simple: find the area of the equilateral triangle whose sides are each length 1. In fact, this same problem is solved in 8th grade, addressing a different Common Core standard, using the formula for area of a triangle...
Illustrative Mathematics
Base and Height
It is easy to find the area of a triangle where the base and the height are given. But in this resource, it is up to your geometers to identify the base and height of the triangle. In fact, your pupils will learn that there are three...
Illustrative Mathematics
Lines of Symmetry for Triangles
What can symmetry tell us about triangles? After looking at four examples, learners will come to realize that lines of symmetry are different for equilateral, isosceles, and scalene triangles. Use this guided practice activity as an...
Illustrative Mathematics
Are These Right?
Is that a right triangle or a wrong triangle? Young mathematicians look at eleven different shapes and use a measuring tool of their choice to determine which triangles have right angles. Consider cutting out sets of the shapes to...
Illustrative Mathematics
Running on the Football Field
Make your class into Pythagorean theorem fanatics in no time. What a great resource to get your sports enthusiasts into the math game! Read the commentary so you can you can strategize how to apply the three math practices.
Illustrative Mathematics
Painting a Barn
When painting a barn you have to calculate surface area, and that is exactly what this resource is about. Not only will your future home owners calculate the surface area, but also the cost. It is a real-life problem that every that...
Illustrative Mathematics
Finding Areas of Polygons, Variation 1
An exercise in finding the area of polygons by decomposing into triangles and composing into rectangles is the focus of this resource. Make several copies of the worksheet for each participant. Ask learners to use colored pencils to...
Illustrative Mathematics
Same Base and Height, Variation 2
This is a good model for learners to visualize triangles of the same base and height. They can can begin to comprehend that these triangles will have the same area no matter how the triangle is drawn. It is part of a series of resources...
Illustrative Mathematics
Area of a Trapezoid
Here is a straightforward example of how to apply the Pythagorean Theorem to find an unknown side-length of a trapezoid. Commentary gives additional information on proving that the inside of the trapezoid is a rectangle, but is...
Curated OER
Section 2.5 - Problem Solving (Part B)
Trying to figure out the perimeter of a geometric figure? Here are a few word problems to set up algebraic equations to solve for perimeter. There are also some word problems to set up algebraic equations to solve for angles in a...
Curated OER
Spotting Polygons
See all sides of the story with a learning exercise on geometric shapes! After studying the example at the top, which matches polygons with solid figures, second graders circle shapes that are named in the directions. Next, they match...
Curated OER
Evergreen Tree
Learners use a ruler to make measurements, and to create triangles and a rectangle. They take the shapes they've made and assemble them into an evergreen tree image. This simple, yet effective, lesson would be ideal for young learners...
Curated OER
Same Shape and Size
Can your kindergartners recognize shapes? What about when they are in different orientations? Youngsters study groups of shapes to determine which have the same shape and size. Two of the groups have triangles and ovals, and the other...
Curated OER
Worksheet 7: Slope and Tangents
Providing both review and practice problems, this worksheet prompts students to answer five questions having to do with slope, tangents lines, graphing, the Squeeze Theorem, differentiable functions and derivatives. This activity could...
Curated OER
Naming Polygons
What polygon is this? Young geometers categorize shapes by circling all the quadrilaterals in a set of figures. Next, they write the names of 10 polygons using a visual guide as reference. Review the guide together before they start if...
Curated OER
2-Dimensional Shapes: Naming Shapes
Get to know eight shapes by name: square, rectangle, triangle, pentagon, hexagon, and octagon. Young geometers write the correct name below each of these shapes, using a word bank for guidance. Then, they draw two of the...
Curated OER
Naming 2-Dimensional Shapes
Inside each of these two-dimensional shapes, scholars identify the figure by writing its name. There is a word bank for them to work from, but some shape names are used multiple times. There are six identifiers they use: pentagon,...