Illustrative Mathematics
What is a Trapezoid? (Part 2)
This collaborative activity investigates the meaning of a trapezoid and a parallelogram. It begins by presenting two different definitions of a trapezoid. Learners are to reason abstractly the difference between the two definitions and...
Illustrative Mathematics
A Midpoint Miracle
Young geometers develop one of the fundamental properties of quadrilaterals (connecting side midpoints gives a parallelogram) in this short but thought-provoking exercise. Using a combination of hands-on techniques and abstract algebraic...
Illustrative Mathematics
What Shape Am I?
Sharpen your pencil and grab a ruler, it's time to draw some quadrilaterals! Given the definition of a parallelogram, rectangle, and rhombus, learners draw examples and nonexamples of each figure. The three definitions are...
Illustrative Mathematics
Lines of Symmetry for Quadrilaterals
Explore how lines of symmetry help define different categories of quadrilaterals. Looking at a square, rectangle, trapezoid, and parallelogram, young mathematicians discover that each shape has its own, unique symmetry. Encourage your...
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...
Curated OER
Symmetries of a Quadrilateral I
Learners examine the properties of quadrilaterals from the point of view of rigid motion. Different types of quadrilaterals are characterized by their symmetries, so learners explore the symmetries of a described quadrilateral to...
Illustrative Mathematics
Right Triangles Inscribed in Circles II
So many times the characteristics of triangles are presented as a vocabulary-type of lesson, but in this activity they are key to unraveling a proof. A unique attack on proving that an inscribed angle that subtends a diameter must be a...
National Council of Teachers of Mathematics
Nctm: Illuminations: Igd: Area of a Parallelogram
This applet will show you how to divide the parallelogram into pieces, arrange them together to form a rectangle, and then use the formula for the area of a rectangle to find the area of the parallelogram.
Texas Instruments
Texas Instruments: Discovering Properties of Parallelograms, Kites & Trapazoids
This activity allows the teacher to cover the properties of a parallelogram, rectangle, rhombus, square, kite, and trapezoid in two days (90 min. block scheduling) Using a group setting students discover these properties using the Cabri...
Texas Instruments
Texas Instruments: Special Parallelograms
In this activity, students will study special types of parallelograms like rhombus and rectangle, and investigate properties related to their diagonals.
The Math League
The Math League: Area and Perimeter
This tutorial provides a brief introduction about what area is, then gives the formulas for area of a square, rectangle, parallelogram, trapezoid, triangle, and circle. Examples of each formula are provided.
Varsity Tutors
Varsity Tutors: Hotmath: Graphing Calculator Practice Problems: Quadrilaterals
Practice using your graphing calculator for constructing a parallelogram, a rhombus, a kite, a trapezoid, an isosceles trapezoid, a rectangle, and a square. If you get stumped or if you would like to check your work, then select the View...
Texas Instruments
Texas Instruments: Area Formulas App
Students review the definition and area formula for the rectangle, square, parallelogram, triangle, trapezoid, and circle.
Texas Instruments
Texas Instruments: Getting Started With Area Formulas App
Calculate the Area of a Trapezoid This Concept Handheld Software Application reviews the definition and area formula for the rectangle, square, parallelogram, triangle, trapezoid, and circle.
BBC
Bbc: Area in General
You can pick up some valuable pointers on how to find the area of a triangle, rectangle, and other quadrilaterals. When you finish working your way through the pages you can take an on-line "Test Bite," and check your understanding.
National Council of Teachers of Mathematics
The Math Forum: Find the Area of the Shape!
Try to figure out the area of this challenging shape. In order to view the images, you will need to use JavaSketchpad.
Varsity Tutors
Varsity Tutors: Hotmath: Practice Problems: Quadrilateral Exercises
Twenty-four problems cover the topic of working with quadrilaterals in different settings. They are given with each step to the solution cleverly revealed one at a time. You can work each step of the problem then click the "View...
National Council of Teachers of Mathematics
The Math Forum: Seventh Grade Math: Area and Perimeter
Learn how to enlarge drawings, figure out how much tile to buy to cover a specific floor, and learn about area and perimeter. These and other lesson plans are provided, including a fun interdisciplinary plan featuring dragons.
Illustrative Mathematics
Illustrative Mathematics: 4.g What Shape Am I?
In this task, students ultimately use the definitions they are given for three types of quadrilaterals and what they know about parallel sides to identify that a square fits all the definitions and explain why. Aligns with 4.G.A.2.
Rice University
Rice University: Cynthia Lanius: Hidden Polygon Activity
On this site students are instructed to locate different types of polygons on triangle grid paper. This page can be printed so that students can actually draw them. It also gives a definitions link for each polygon.