University of Cambridge
University of Cambridge: Nrich: Numerically Equal
The challenge for this problem is to see if you can find rectangular shapes that have the same number for their perimeter and area. Solutions are available at this one page website.
Calculator Soup
Calculator Soup: Isosceles Triangles Calculator
Use this calculator to find the sides, perimeter, area, semiperimeter, and altitude of an isosceles triangle.
Texas Instruments
Texas Instruments: What Goes Around Comes Around but Can You Measure It?
In this activity, students find the area and the perimeter for several geometric shapes. They also determine the surface area and volume of spheres.
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.
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.
Math Playground
Math Playground: Geometry Board
Create polygons by stretching bands over pegs on this geometry board. Then find the area and perimeter of the shape you created.
Curated OER
Find Out Things About a Square
Webmath will calculate the side length, diagonal length, perimeter, area, or volume, given the side, perimeter, diagonal, or area. This site also displays formulas for a square.
Khan Academy
Khan Academy: Circumference of a Circle
Find the circumference of a circle when given either the radius or diameter.Find the radius or diameter of a circle when given the circumference.Students receive immediate feedback and have the opportunity to try questions repeatedly,...
Khan Academy
Khan Academy: Radius and Diameter
Practice finding the radius and diameter of a circle using both vocabulary and visuals. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Varsity Tutors
Varsity Tutors: Hotmath: Algebra Review: Square
Find a quick, concise explanation of a square. An example is given and clearly explained.
That Quiz
That Quiz: Practice Test: Triangles
Test your knowledge on the attributes of triangles. There are eleven levels that may be completed with or without a timer.