Texas A&M University
Wtamu Virtual Math Lab: Beginning Algebra: Formulas
This tutorial will show you how using formulas can help you solve problems. Include formulas for various geometric shapes and steps showing how to use them.
Illustrative Mathematics
Illustrative Mathematics: G Gpe Equal Area Triangles on the Same Base I
This task is a relatively easy application of the formula for the area of a triangle and the use of parallel lines. Aligns with G-GPE.B.5.
The Math League
The Math League: Area and Perimeter
This tutorial provides a brief introduction about what area is, then gives the formulas for area of a square, rectangle, parallelogram, trapezoid, triangle, and circle. Examples of each formula are provided.
Mr. Martini's Classroom
Mr. Martini's Classroom: Area of Triangles, Trapezoids & Parallelograms
Students solve for the area of rectangles, squares, triangles, trapezoids, and parallelograms.
ClassFlow
Class Flow: Area of Polygons
[Free Registration/Login Required] This flipchart provides students with notes and practice with using formulas for finding the area of triangles and quadrilaterals.
Better Lesson
Better Lesson: Finding the Area Review and Assessment
Sixth graders find the area of rectangles, triangles, parallelograms, and trapezoids by using formulas or by composing into rectangles or triangles.
Khan Academy
Khan Academy: Area of Triangles
Demonstrates the logic behind the formula for the area of a triangle. Includes several practice problems and their explanations.
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
Homeschool Math
Homeschool Math: Area of Triangles
This lesson presents the idea that the area of any triangle is exactly half of a certain parallelogram -- thus we get the familiar formula of multiplying the base and the altitude and taking half of that. The lesson contains varied...
Texas Instruments
Texas Instruments: Surround and Be Found! Triangular Areas, That Is!
In this activity, students use the Geoboard to determine the area of triangles using the surrounding rectangle technique. They also develop and use formulas to determine the area of triangles. [Requires Adobe Reader.]
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.
Texas Instruments
Texas Instruments: Heron's Formula
This activity allows students to find the area of a triangle using Heron's formula.
Texas Instruments
Texas Instruments: Investigating Properties of Trapezoids
Students draw trapezoids and investigate their properties. They derive the area formula for a triangle from the area formula for a trapezoid. They also investigate the terms: Isosceles trapezoid and Tessellation. Numerous supplementary...
Shmoop University
Shmoop: Basic Geometry: Area (Polygon, Triangle, Circle, Square)
The geometry resource investigates the area of polygons, triangles, circles, and squares. Formulas and examples are included.
ClassFlow
Class Flow: Area of Triangles
[Free Registration/Login Required] This flipchart explores the formula for finding the area of a triangle. Examples and hints are given to help students. A video clip is included, showing how to find the height of a triangle, given the...
Illustrative Mathematics
Illustrative Mathematics: 6.g Same Base and Height, Variation 2
This is the second version of a task asking students to find the areas of triangles that have the same base and height. This presentation is more abstract as students are not using physical models. They still determine the area of each...
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...
Wolfram Research
Wolfram Math World: Midpoint
This MathWorld site offers a lesson on finding the midpoint of a line segment using a compass and finding the midpoint of the sides of a triangle. This site also has an interesting way of drawing two triangle with equal area by finding...
OER Commons
Oer Commons: Polygons
Seventh graders find the area of regular polygons, recalling what they already know about the area of geometric shapes and generalizing a formula for any regular polygon.
Purple Math
Purplemath: Geometry Word Problems: Introduction
Introduces how to set up and solve simple geometric-figure word problems. Includes advice regarding formulas to memorize.