National Council of Teachers of Mathematics
Nctm: Illuminations: Igd: Area of a Parallelogram
Use this interactive tool to learn how to find the area of a parallelogram. Click on "Instructions" for details on how to use this tool. Click on "Explore" for more ideas.
National Council of Teachers of Mathematics
Nctm: Illuminations: Area of Triangles
To find the area of a triangle, try to make a parallelogram using a copy of the triangle.
Oswego City School District
Regents Exam Prep Center: Area of a Triangle and Parallelogram Using Trig
How can trigonometry be used to find the area of a triangle or parallelogram? Does the triangle need to be a right triangle, and how accurate can the results possibly be? The answers to these questions are found here along with several...
Texas Instruments
Texas Instruments: Math Today Thirsty for Oil
In this activity, students can use the USA TODAY Infograph 'Thirsty for oil' to explore the area of a trapezoid and determine how to find area. Students will find the area of a parallelogram and use this to determine a formula for the...
Other
Algebra Lab: Areas and Perimeters of Triangles and Special Quadrilaterals
Learn how to find the areas and perimeters of triangles and special quadrilaterals.
Science and Mathematics Initiative for Learning Enhancement (SMILE)
Smile: The Area of a Circle
An investigative approach is given to exploring finding the area of a circle.
CPALMS
Cpalms: Building Graduation Caps
[Free Registration/Login Required] In this lesson plan, students build geometric models of graduation caps using stiff paper. The activity requires the application of skills in finding surface area, understanding similarity, knowing the...
Cuemath
Cuemath: Quadrilaterals
Explore the world of quadrilaterals and their properties. Find answers to questions like what are quadrilaterals, how they are formed, easy ways to identify them, and commonly seen quadrilaterals around us.
Purple Math
Purplemath: Determinant Word Problems
Matrix determinants can be used to solve many algebra and geometry word problems. Among them: finding the area of a triangle, finding the area of a parallelogram, and finding the equation of a line between two points. These three...
Varsity Tutors
Varsity Tutors: Hotmath: Algebra Review: Rhombus
Find a quick, concise explanation of a rhombus. An example is given and clearly explained.