Discovery Education
Discovery Education: Web Math: Find Out Things About a Right Triangle
Gives basic info about a right triangle. Also students can substitute values for sides or angles in order to find missing values. The method for solving is then explained.
Khan Academy
Khan Academy: Find Base and Height on a Triangle
Identify the height of a triangle when given the base. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Khan Academy
Khan Academy: Area Challenge
Practice solving problems involving triangles, parallelograms, and composite figures. Exercises include decimals, fractions, and word problems. Area of circles is not included. Students receive immediate feedback and have the opportunity...
Texas Instruments
Texas Instruments: Move Along Little Vertex
In this activity, students use the Geoboard to determine the area of triangles having the same base and same height.
Better Lesson
Better Lesson: Finding the Area of a Trapezoid
Sixth graders find the area of a trapezoid by decomposing it into triangles and using the formula
Illustrative Mathematics
Illustrative Mathematics: 8.g Circle Sandwich
Eighth graders are presented with a drawing of a large square inscribed by a circle which is itself inscribed by a second square. They are asked to find the area of the circle outside the smaller square and compare it to the area of the...
Calculator Soup
Calculator Soup: Equilateral Triangles Calculator
An equilateral triangle is a special case of a triangle where all 3 sides have equal length and all 3 angles are equal to 60 degrees.
Homeschool Math
Homeschool Math: Area of Right Triangles
This lesson presents the idea that the area of any right triangle is exactly half of a certain rectangle, and contains varied exercises for students.
Learning Wave Communications
Learning Wave: Geometry, Section 2
Geometry concepts are briefly discussed at this site, including volume of a cylinder, parallelograms, circles, trapezoids, and triangles. Sample problems and applications are included for practice.
Math Slice
Math Slice: Area & Perimeter: Math Worksheets
This tool allows you to create worksheets of word problems at varying levels of difficulty where students must calculate the area or perimeter of different polygon shapes. You can choose to set up the page using any of these polygon...
Homeschool Math
Homeschool Math: Area of Parallelograms
This lesson presents the idea that the area of any right triangle is exactly half of a certain rectangle, and contains varied exercises for students.
Math Drills
Math Drills: Measurement Worksheets
Download these free worksheets to sharpen your measurement skills. Sheets focus on temperature, conversion, area and perimeter, volume, and more.
Calculator Soup
Calculator Soup: Right Triangles Calculator
Use this calculator to find the unknown angles in a right triangle using the Pythagorean Theorem. Once you know the sides you can calculate the perimeter, semiperimeter, area, and the altitudes.
Other
Algebra Lab: Areas and Perimeters of Triangles and Special Quadrilaterals
Learn how to find the areas and perimeters of triangles and special quadrilaterals.
BBC
Bbc: Bitesize: Maths: 2 D Shapes
Learn about the properties of 2-D shapes: circles, triangles, polygons, and quadrilaterals. Includes information, video, and examples about each, with games and quizzes for reinforcement.
That Quiz
That Quiz: Triangulos
These interactive activities are designed to examine the mathematical concepts of length, perimeter, and area. These activities may be used to develop students' understanding of these mathematical concepts.
Ministerio de Educacion, Cultura y Deporte (Spain)
Cnice: Relacion De Ejercicios Interactivos.
In Spanish. Interactive activities online on various geometric and trigonometric concepts such as area, perimeter, secants, tangents, etc. A terrific resource for students. Site is organized acoording to shape. (triangle, quadrilaterals,...
Math Open Reference
Math Open Reference: Polygons
Get the definition and properties of a polygon. Then explore such topics as: 1) types of polygon 2) area 3) Perimeter 4) angles associated with polygons and 5) names of polygons.
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.
CK-12 Foundation
Ck 12: Geometry: Applications of the Pythagorean Theorem
[Free Registration/Login may be required to access all resource tools.] In this lesson students use the Pythagorean Theorem to find perimeter and area. Students examine guided notes, review guided practice, watch instructional videos and...
Better Lesson
Better Lesson: Remarkable Rectangles
Rectangle is SO MUCH like triangle! Those darned angles--they'll get beginning learners! This is a fun way to practice rectangle!
Cool Math
Coolmath: Precalculus Basic Formulas to Know
This CoolMath resource provides an introduction to some Precalculus formulas.
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.
Calculator Soup
Calculator Soup: Regular Polygon Calculator
Use this calculator to calculate properties of a regular polygon. Enter any 1 variable plus the number of sides or the polygon name. Calculates side length, inradius, circumradius, area, and perimeter.