CK-12 Foundation
Ck 12: Geometry: Parallelograms
[Free Registration/Login may be required to access all resource tools.] This concept teaches students properties of and theorems about parallelograms and how to apply them.
Illustrative Mathematics
Illustrative Mathematics: 6.g Same Base and Height, Variation 1
Make the following triangles on a geoboard. Remember that the pegs are equally spaced in a square grid. Compare the areas of the triangles. Aligns with 6.G.A.1.
Illustrative Mathematics
Illustrative Mathematics: 6.g Base and Height
The purpose of this task is to help students understand what is meant by a base and its corresponding height in a triangle and to be able to correctly identify all three base-height pairs. Aligns with 6.G.A.1.
Mr. Martini's Classroom
Mr. Martini's Classroom: Teacher's Figure Library: Geometric Figures
This interactive resource provides an example picture of the geometric figure chosen by students to review.
Calculator Soup
Calculator Soup: Rectangle Calculator
Use this calculator if you know 2 values for the rectangle, including 1 side length, along with area, perimeter, or diagonals and you can calculate the other 3 rectangle variables. A square calculator is a special case of the rectangle...
Vernet -Virtual Education Resources Network
Salon Hogar: Referencia Rapida De Formulas Geometricas
This site provides the user with a useful reference to different geometric forms, their elements, formulas, and areas. Entirely in Spanish.
Illustrative Mathematics
Illustrative Mathematics: 3.md Shapes and Their Insides
The purpose of this task is to help students differentiate between a polygon and the region inside of a polygon so that they understand what is being measured when the perimeter and area are being found. Aligns with 3.MD.D.
Alabama Learning Exchange
Alex: Geometric Quilts
Students will use a square to investigate other polygonal shapes that can be formed. Students will work with these polygons to make designs that will later constitute cooperatively designed quilts. The quilts will be made by translating,...
Ministry of Education and Universities of the Region of Murcia (Spain)
Ministerio De Educacion Y Ciencia: Medidas De Poligonos
In Spanish. Interactive activities dealing with the definition, angles and area of a polygon.
Alabama Learning Exchange
Alex: It's in the Bag
This lesson is a unique and fun way to review perimeter, angles, and types of adjectives. Students pick an object from the classroom that will fit in a paper lunch bag. They investigate their object and fill in the attached sheet. You...
Wolfram Research
Wolfram Math World: Squares
MathWorld provides multiple definitions and formulas for the mathematical term, square.
Varsity Tutors
Varsity Tutors: Hotmath: Graphing Calculator Practice Problems Geometry
Practice using your graphing calculator for Geometry problems. If you get stumped or if you would like to check your work, then select the View Solution button, which is located directly under each problem.
National Council of Teachers of Mathematics
Nctm: Figure This: Windshield Wipers
Test your mathematical aptitude with challenge exploring the concepts of measurement and geometry. Find the area of the windshield wipers to figure out who sees better in the rain, car drivers or truck drivers. An activity from the NCTM...
Jim Loy
Jl's Math Page: The Golden Rectangle and the Golden Ratio
This is a personal site from Jim Loy that describes the golden rectangle and the golden ratio. Includes several diagrams and pictures as well as formulas. A good background in math is helpful.
Calculator Soup
Calculator Soup: Square Calculator
Use this square calculator to find the side length, diagonal length, perimeter, or area of a geometric square. Given any 1 variable you can calculate the other 3 unknowns.
Texas Instruments
Texas Instruments: Circles: Circumference and Area
The idea of perimeter can be applied not only to polygons but to circles as well. The same idea can be said for the area of a circle. (Continued. See "before the activity.") [Requires Adobe Reader.]