Curated OER
Finding the Area of Polygons
Third graders are exposed to finding the area of polygons by decomposing figures and recomposing them into rectangles. This strategy allows children to expand on their prior knowledge of constructing shapes by rearranging parts into...
Shodor Education Foundation
Triangle Area
While the lesson plan focuses on right triangles, this activity offers a great way to practice the area of all triangles through an interactive webpage. The activity begins with the class taking a square paper and cutting in in half; can...
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...
Teach Engineering
Using Map Scales to Figure Distances and Areas
The asteroid is getting closer and the question is whether the state of Alabraska is large enough for the shelter calculated in the previous activity. Teams determine the scale of their project and then use the scale on the map to...
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
The Square Counting Shortcut
An excellent lesson plan that encourages students to discover how complex figures can be broken into simpler shapes when measuring area. Working with block letters, learners are given the freedom to develop their own strategies for...
Education Development Center
Choosing Samples
What makes a good sample? Your classes collaborate to answer this question through a task involving areas of rectangles. Given a set of 100 rectangles, they sample a set of five rectangles to estimate the average area of the figures. The...
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...
Education Development Center
Rectangles with the Same Numerical Area and Perimeter
Is it possible for a rectangle to have the same area and perimeter? If you disregard units, it happens! In a challenging task, groups work to determine the rectangles that meet these criterion. The hope is that learners will naturally...
Curated OER
Unit Squares and Triangles
This is an interesting geometry problem. Given the figure, find the area of a triangle that is created by the intersecting lines. The solution requires one to use what he/she knows about coordinate geometry, as well as triangle and angle...
101 Questions
R2D2 Post-Its
You can't go wrong with Star Wars! A video set to the Star Wars theme song presents a problem solving situation. The task? Determine how many small Post-It notes will fit on a bulletin board. The problem requires individuals to compare...
Illustrative Mathematics
Equal Area Triangles on the Same Base II
A deceptively simple question setup leads to a number of attack methods and a surprisingly sophisticated solution set in this open-ended problem. Young geometers of different strengths can go about defining the solutions graphically,...
Illustrative Mathematics
Same Base and Height, Variation 1
Four triangles are depicted for learners to construct on a geoboard. They compute and compare the areas, and so meet one of the sixth grade Common Core standards for geometry. Note that the set of triangles does not include a right...
Howard County Schools
Building a Playground
Scholars crave practical application. Let them use the different models of a quadratic function to plan the size and shape of a school playground. They convert between the different forms and maximize area.
Curated OER
Shapes and Their Insides
Learners follow a series of instructions for drawing and coloring different shapes in order to learn the difference between the perimeter and area of a polygon. Then they are asked to find the perimeter and area of a 3x4 rectangular...
Illustrative Mathematics
Converting Square Units
Jada has a rectangle board that is measured in inches. Young learners confirm their understanding of converting inches to feet. Then they find the area in square feet. Jada thinks she has a short-cut to convert inches square to square...
PBL Pathways
Total Cost to Produce the Turbo Blender
Class members blend their knowledge of functions and problem-solving skills to provide business advice to the Turbo Blender manufacturers. Through a project-based approach, learners examine marginal cost data to produce a function. They...
Illustrative Mathematics
Overlapping Squares
The objective of this activity is to find the percent of the area of a two squares overlapping. Mathematicians find the ratio of area for the part that overlaps to the rectangle formed. The final answer is a percent as a rate per 100....
National Park Service
Fitting In
Birds help other birds find food? Scholars are placed into one of five groups of different birds. Each group then "feeds" on letters of paper in a field and gather five pieces per person. As each group plays, more food is exposed,...
Exploratorium
Making a Translation Tesselation
Make masterful art using math. An interesting activity has learners create artwork involving tesselations. First they cut out a base shape from index cards, then they apply translations to complete their masterpieces.
Illustrative Mathematics
Shape Hunt Part 2
Shapes are everywhere in the world around us, from rectangular doors to the circular wheels of a car. The second lesson in this series opens the eyes of young mathematicians to this wonderful world of shapes as they search the classroom,...
Illustrative Mathematics
Toilet Roll
Potty humor is always a big hit with the school-age crowd, and potty algebra takes this topic to a whole new level. Here the class develops a model that connects the dimensions (radii, paper thickness, and length of paper) of a common...
West Contra Costa Unified School District
Division (No Remainders)
Help young mathematicians build a solid understanding of division with this base ten block activity. With the help of these popular math manipulatives, children model different math problems in order to reinforce the connection between...
Illustrative Mathematics
Why Randomize?
Your statisticians draw several samplings from the same data set, some randomized and some not, and consider the distribution of the sample means of the two different types of samplings. The exercise demonstrates that non-random samples...