Activity
University of Georgia

University of Georgia: Problem Solving With Heron's Formula

For Students 9th - 10th Standards
From the University of Georgia, this tutorial provides exercises and problems using Heron's Formula for the area of a triangle, makes use of several problem representation methods, including a graph.
Handout
Wolfram Research

Wolfram Math World: Heron's Formula

For Students 9th - 10th
This site provides a detailed overview of Heron's Formula. Content includes a definition, example, and formula.
Unit Plan
Varsity Tutors

Varsity Tutors: Hotmath: Review: Area

For Students 9th - 10th Standards
Find a quick, concise explanation of area and the formulas for different shapes. An example is given to help you understand how find the area of a shape. The area formulas are listed for different types of shapes.
Unit Plan
Shmoop University

Shmoop: Basic Geometry: Area Formulas

For Students 9th - 10th Standards
The geometry resource investigates the area of polygons, triangles, circles, and squares. Formulas, examples, and practice exercises are included.
Unit Plan
Shmoop University

Shmoop: Basic Geometry: Area (Polygon, Triangle, Circle, Square)

For Students 9th - 10th Standards
The geometry resource investigates the area of polygons, triangles, circles, and squares. Formulas and examples are included.
Whiteboard
ClassFlow

Class Flow: Area of Polygons

For Teachers 6th - 8th Standards
[Free Registration/Login Required] This flipchart provides students with notes and practice with using formulas for finding the area of triangles and quadrilaterals.
Whiteboard
ClassFlow

Class Flow: Area of Triangles

For Teachers 3rd - 5th Standards
[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...
Lesson Plan
Better Lesson

Better Lesson: Finding the Area Review and Assessment

For Teachers 6th Standards
Sixth graders find the area of rectangles, triangles, parallelograms, and trapezoids by using formulas or by composing into rectangles or triangles.
Activity
Michigan Technological University

Heron's Formula for Computing Triangle Area Using External Functions

For Students 9th - 10th
Explains how to use Heron's formula with external functions using computer programming. Includes detailed directions.
Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: 6.g Same Base and Height, Variation 2

For Teachers 5th - 8th Standards
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...
Activity
Math Is Fun

Math Is Fun: Heron's Formula

For Students 9th - 10th
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.
Unit Plan
CK-12 Foundation

Ck 12: Trigonometry: Heron's Formula

For Students 10th - 12th
[Free Registration/Login may be required to access all resource tools.] Find the area of a triangle when all three sides are known.
Activity
Texas Instruments

Texas Instruments: Surround and Be Found! Triangular Areas, That Is!

For Teachers 6th - 8th Standards
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.]
Unit Plan
CK-12 Foundation

Ck 12: Trigonometry: Heron's Formula

For Students 10th - 12th
[Free Registration/Login may be required to access all resource tools.] This lesson covers Heron's Formula and problem solving using trigonometry.
Activity
Texas Instruments

Texas Instruments: Calculating the Area of a Triangle Using Heron's Formula

For Teachers 9th - 10th
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....
Handout
Math Open Reference

Math Open Reference: Heron's Formula

For Students 9th - 10th
Learn about corresponding angles with this resource which offers detailed explanations, examples, and interactives. Subjests covered include the area of a triangle. Links to related topics.
Handout
Math Open Reference

Math Open Reference: Area of an Equilateral Triangle

For Students 9th - 10th Standards
Learn about the area of an equilateral triangle with this helpful reference tool. Provides a detailed definition, examples, and an internet activity that enhances further explanation. Includes links to related topics.
Activity
The Math League

The Math League: Area and Perimeter

For Students 9th - 10th Standards
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.
Unit Plan
CK-12 Foundation

Ck 12: Trigonometry: Alternate Formula for the Area of a Triangle

For Students 10th - 12th
[Free Registration/Login may be required to access all resource tools.] An alternate formula for the area of a triangle.
Activity
University of Illinois

University of Illinois: Calculation of Triangle Area

For Students 9th - 10th
Discusses how to find the area of a triangle using Heron's formula and provides interactive examples and problems you can solve.
Lesson Plan
Better Lesson

Better Lesson: Finding the Area of a Trapezoid

For Students 6th Standards
Sixth graders find the area of a trapezoid by decomposing it into triangles and using the formula
Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G C Mutually Tangent Circles

For Teachers 9th - 10th Standards
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...
Interactive
Mocomi & Anibrain Digital Technologies

Mocomi: What Is Heron's Formula?

For Students 2nd - 8th
Define's Heron's Formula and provides examples for how to use the formula to calculate the area of a triangle.
Unit Plan
Vernet -Virtual Education Resources Network

Salon Hogar: Referencia Rapida De Formulas Geometricas

For Students 9th - 10th Standards
This site provides the user with a useful reference to different geometric forms, their elements, formulas, and areas. Entirely in Spanish.