Texas Instruments
Texas Instruments: Area Formulas App
Students review the definition and area formula for the rectangle, square, parallelogram, triangle, trapezoid, and circle.
Math Open Reference
Math Open Reference: Area of a Rectangle
Learn about the area of a rectangle with this helpful reference tool. Provides a detailed definition and interactive activities that enhance further explanation. Includes links to related topics.
K-5 Math Teaching Resources
K 5 Math Teaching Resources: Comparing Rectangles [Pdf]
Comparing Rectangles is a learning activity that applies skills that compare rectangles.
Texas Instruments
Texas Instruments: Perimeter of a Rectangle With Fixed Area
Students will investigate the relationship between the base of a rectangle with area of 35 or 36 and its perimeter.
Texas Instruments
Texas Instruments: Dimensions and Area
In this activity, students discover the relationship between a change in the dimensions of a rectangle and the change in the corresponding area.
Math Open Reference
Math Open Reference: Perimeter of a Rectangle
Learn about the perimeter of a rectangle with this handy reference guide. Provides a detailed definition, examples, and interactive activities that enhance further explanation. Includes links to related topics.
Texas Instruments
Texas Instruments: Building a Better Pet Run
This activity is designed to make students realize that area of a rectangle changes for different widths.
Texas Instruments
Texas Instruments: Math Today Wildfires Nearly Snuffed
Students can use the data to explore the relationship between area and perimeter for rectangles and circles and they will make generalizations about the shape of the rectangle that will produce the smallest perimeter.
National Council of Teachers of Mathematics
Nctm: Illuminations: Scale Factor
The interactive applet allows learners to explore the relationships between side length, area, and perimeter. Students see how changes in the scale factor influence the ratio of areas and perimeters. [Requires Java.]
Texas Instruments
Texas Instruments: Surround and Be Found! Triangular Areas, That Is!
In this activity, students use the Geoboard to determine the area of triangles using the surrounding rectangle technique. They also develop and use formulas to determine the area of triangles. [Requires Adobe Reader.]
Shodor Education Foundation
Shodor Interactivate: Shape Builder
This activity operates in one of two modes: auto draw and create shape mode, allowing you to explore relationships between area and perimeter.
Texas Instruments
Texas Instruments: Cross Fencing Pastures
In this activity, students use the Geoboard to determine the areas of polygons by dissecting them into parts that are squares, rectangles, and triangles.
Analyze Math
Analyze Math: Rectangle Problems
The geometry tutorial investigates rectangles. Topics included are diagonals, area, and perimeter. The activity has several examples with detailed solutions.
Shodor Education Foundation
Shodor Interactivate: Factorize 2
The resource consists of student notes, instructor notes, and an interactive activity. The activity allows learners to find the factors of a given number and then draw the product as the area of a rectangle on a grid.
Shodor Education Foundation
Shodor Interactivate: Factorize
This Shodor site gives a brief explanation of factorization, and it allows you "to find all of the factorizations of a given number and then draw the product as the area of a rectangle on a grid."
Shodor Education Foundation
Shodor Interactivate: Perimeter Explorer
Use this applet to find the perimeter of a variety of shapes with the same or different areas.