Activity
University of Virginia

Geometrical Proof of Heron?s Formula

For Students 9th - 10th
Gives a geometrical proof of Heron's formula and discusses its relationship to trigonometry.
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.
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.
Activity
Texas Instruments

Texas Instruments: Heron's Formula

For Teachers 9th - 10th
This activity allows students to find the area of a triangle using Heron's formula.
Handout
University of St. Andrews (UK)

University of St. Andrews: References for Heron of Alexandria

For Students 9th - 10th
This site contains important links on which to learn more about Heron of Alexandria. Is a useful site for anyone doing research on this great mathematician.
Unit Plan
University of British Columbia

University of British Columbia: Heron's Criterion

For Students 9th - 10th
This site from the University of British Columbia describes and provides examples of Heron's Formula.
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.
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.
Unit Plan
Other

Math Pages: Heron's Formula and Brahmagupta's Generalization

For Students 9th - 10th
This resource provides detailed information and pertinent graphs dealing with Heron's Formula and Brahmagupta's Generalization. Useful for any student who is studying these two concepts.
Article
Other

Math Pages: Heron's Formula for Tetrahedra

For Students 9th - 10th
This article explains how Heron's formula is very similar to Pythagoras' Theorem.
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.
Handout
University of St. Andrews (UK)

University of St. Andrews: Biography of Hero

For Students 9th - 10th
This University of St. Andrews site contains information on the life of Heron as well as his accomplishments.
Unit Plan
CK-12 Foundation

Ck 12: Trigonometry: Introduction to the Triangle Area Formula

For Students 10th - 12th Standards
[Free Registration/Login may be required to access all resource tools.] This lesson covers how to find the area of a triangle using sine.
Handout
Math Open Reference

Math Open Reference: Heron

For Students 9th - 10th
Learn about the life and mathematical discoveries of Greek mathematician, Heron.
Handout
Wolfram Research

Wolfram Science World: Heron of Alexandria (Ca. 75 Ad)

For Students 9th - 10th
Greek mathematician who was mainly interested in practical studies of mechanics and engineering. He dealt with a number of such problems in his work Dioptra. He is best known today for Proposition 1.8 of his Metrica, which is now known...
Activity
Analyze Math

Analyze Math: Trapezoid Problems

For Students 9th - 10th Standards
The geometry tutorial examines the area, length, and vertices of a trapezoid. Topics include Heron's formula. The activity has several examples with detailed solutions.
Handout
Math Is Fun

Math Is Fun: Area of Triangles Without Right Angles

For Students 9th - 10th Standards
Learn how to find the area of triangles without right angles. Find the formula to use depending on the information you know about the triangle: base and height, three sides, or two sides and an angle.
Unit Plan
Oswego City School District

Regents Exam Prep Center: Area of a Triangle and Parallelogram Using Trig

For Students 9th - 10th Standards
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...
Graphic
Curated OER

University of British Columbia: Heron's Criterion

For Students 9th - 10th
This site from the University of British Columbia describes and provides examples of Heron's Formula.
Graphic
Curated OER

University of British Columbia: Heron's Criterion

For Students 9th - 10th
This site from the University of British Columbia describes and provides examples of Heron's Formula.
Graphic
Curated OER

University of British Columbia: Heron's Criterion

For Students 9th - 10th
This site from the University of British Columbia describes and provides examples of Heron's Formula.
Graphic
Curated OER

University of British Columbia: Heron's Criterion

For Students 9th - 10th
This site from the University of British Columbia describes and provides examples of Heron's Formula.
Graphic
Curated OER

University of British Columbia: Heron's Criterion

For Students 9th - 10th
This site from the University of British Columbia describes and provides examples of Heron's Formula.
Graphic
Curated OER

University of British Columbia: Heron's Criterion

For Students 9th - 10th
This site from the University of British Columbia describes and provides examples of Heron's Formula.