CK-12 Foundation
Ck 12: Geometry: Area and Perimeter of Triangles
[Free Registration/Login may be required to access all resource tools.] In this lesson students calculate the area and perimeter of a triangle. Students examine guided notes, review guided practice, watch instructional videos and attempt...
National Council of Teachers of Mathematics
The Math Forum: Find the Area of the Shape!
Try to figure out the area of this challenging shape. In order to view the images, you will need to use JavaSketchpad.
BBC
Bbc: Area in General
You can pick up some valuable pointers on how to find the area of a triangle, rectangle, and other quadrilaterals. When you finish working your way through the pages you can take an on-line "Test Bite," and check your understanding.
Texas Instruments
Texas Instruments: Calculating the Area of a Triangle Using Heron's Formula
Students will measure the lengths of the sides of three different triangles and apply Heron's Formula to calculate the area in acres. The measurements for this activity may be done outside or, using a specified scale, completed inside....
Texas Instruments
Texas Instruments: Getting Started With Area Formulas App
Calculate the Area of a Trapezoid This Concept Handheld Software Application reviews the definition and area formula for the rectangle, square, parallelogram, triangle, trapezoid, and circle.
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.
University of Cambridge
University of Cambridge: Nrich: Adding Triangles
Sharpen your logic and geometry skills by finding the area of a triangle. Solution available.
ClassFlow
Class Flow: Review of Area
[Free Registration/Login Required] This flipchart is a review of calculating the area of squares, rectangles, and triangles for fifth graders. It also includes problems that work backwards from the area to find missing dimensions. It...
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...
University of Illinois
University of Illinois: Calculation of Triangle Area
Discusses how to find the area of a triangle using Heron's formula and provides interactive examples and problems you can solve.
Harvard University
Harvard Smithsonian: Everyday Classroom Tools
The focus of this series of lessons is to engage students in an exploration of the world around them. The emphasis is on inquiry as students learn about the earth, sun, light, shapes and more.
Texas Instruments
Texas Instruments: Triangulation Problem
In this Computer Algebra System (CAS) activity, students use 'landscape' paper and fold the top left corner of the page so that it just touches the bottom of the page. They calculate the area of the triangle formed by the bottom left...
Math Is Fun
Math Is Fun: Heron's Formula
Learn a formula, created thousands of years ago, that you can use to calculate the area of a triangle if you know all three sides' lengths.