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...
Curated OER
Operation Spaghetti
Find the math in recipes. Young chefs will follow a recipe and investigate the total cost for materials. They measure amounts of food necessary for the recipe and compute the per person cost.
ConnectED
Crime Scene Investigation
How exactly does a crime scene investigation work? The resource, a unit on criminology, covers everything from the deductive reasoning skills needed for detectives to DNA fingerprinting, all the way to how to gather evidence and bring...
EngageNY
Construct an Equilateral Triangle (part 1)
Drawing circles isn't the only thing compasses are good for. In this first installment of a 36-part series, high schoolers learn how to draw equilateral triangles by investigating real-world situations, such as finding the location of a...
Improving Measurement and Geometry in Elementary Schools
Rep Tiles
In addition to the catchy title, this lesson plan provides upper graders an opportunity to more closely scrutinize the attributes of plane figures. In particular, they focus on the similarity of different shapes. Both whole-class and...
Improving Measurement and Geometry in Elementary Schools
The Sum of the Interior Angles of a Polygon
Junior geometers discover that polygons can be decomposed into triangles and that the number of triangles can be determined by a rule. Note that the Geometer’s Sketchpad® software is required to carry out all components of this...
Curated OER
Rep Tiles
Third graders use pattern blocks of one shape at a time to try to create a similar shape. They compare the perimeter of the new figure with the perimeter of the original shape and look for a pattern. Students use the pattern to predict...