Analyze Math
Analyze Math: Area of Triangles
The geometry resource explores the different formulas used to calculate the area of triangles. The applet investigates the angles and sides of a triangle.
Shodor Education Foundation
Shodor Interactivate: Triangle Explorer
This applet allows users to study the nature of triangles and their area. It draws random triangles on a Cartesian coordinate system. The user can determine the area of the triangle using his or her preferred method. After the calculated...
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.
Texas Education Agency
Texas Gateway: Determining Area of Composite Figures
Given composite figures (combinations of rectangles, squares, parallelograms, trapezoids, triangles, semicircles, and quarter circles), students will be able to determine expressions for the area as well as calculate the area of the figure.
Illustrative Mathematics
Illustrative Mathematics: G Gpe Triangle Perimeters
Students are shown two triangles touching points on a coordinate grid and are asked to answer questions about their perimeters. The purpose of this task is to apply the Pythagorean theorem to calculate distances and areas. Aligns with...
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.
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.
Math Planet
Math Planet: Pre Algebra: Measure Areas
Demonstrates how to calculate the area of two-dimensional shapes using formulas. Covers parallelogram, triangle, trapezoid, and circle. Includes a video modeling how to find the area of a circle and a triangle. [0:59]
Calculator Soup
Calculator Soup: Isosceles Triangles Calculator
Use this calculator to find the sides, perimeter, area, semiperimeter, and altitude of an isosceles triangle.
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.
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....
Illustrative Mathematics
Illustrative Mathematics: G Srt Finding the Area of an Equilateral Triangle
This task examines how to calculate the area of an equilateral triangle two ways: using triangle congruence and using trigonometric ratios. Aligns with G-CO.C.10 and G-SRT.C.
Varsity Tutors
Varsity Tutors: Hotmath: Graphing Calculator Practice: Polygons and Area of Plane Figures
Practice using your graphing calculator for measuring and constructing polygons and other plane figures. If you get stumped or if you would like to check your work, then select the View Solution button, which is located directly under...
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.
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.
Illustrative Mathematics
Illustrative Mathematics: G C Mutually Tangent Circles
Three circles are mutually tangent. Students are asked to find the total area of the circles plus the area inside where they meet. Students will need to know how to calculate the area of a circle, a sector of a circle, and an equilateral...
Calculator Soup
Calculator Soup: Cubic Yards Calculator
Use this calculator to calculate cubic yards volume for a variety of different areas. Enter measurements in US units or metric units. Calculate volume from your measurements in inches (in), feet (ft), yards (yd), centimeters (cm), or...
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.