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Lesson Plan
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Curated OER

Dynamic Algebra

For Teachers 9th - 12th Standards
Explore 5 classical problems of algebra.  They will solve problems involving Heron's formula, fractional equations, vector equations, apollonius' sphere, and transversals. The idea is to lead to new perceptions and visual thinking.
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Worksheet
Curated OER

Triangles

For Students 10th
In this triangles worksheet, 10th graders solve 12 different problems that include various angles of triangles. First, they determine the measure of an exterior angle. Then, students determine the measure of any of the base angles of an...
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Lesson Plan
Curated OER

Distance Formula

For Teachers 8th - 10th
Students watch teacher demonstration of distance formula, view non-collinear cities on maps, plot points on coordinate plane, evaluate square roots, compute distance between two points, and use Heron's formula to find area of triangles.
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Lesson Plan
Curated OER

Heron's Formula

For Teachers 9th - 10th
Students use Heron's formula to calculate the area of a triangle. In this geometry lesson, students use three different methods to solve the area of a triangle. They find and construct the incentor and angle bisector of a triangle.
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Worksheet
Curated OER

Heron's Formula Activity

For Students 5th - 6th
In this Heron's formula worksheet, students find the area of scalene triangles to the nearest tenth, showing their work in work space provided. Answers are included on page 2.
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Worksheet
Curated OER

Heron's or Hero's Formula for Area of Scalene Triangle

For Students 7th - 8th
In this Heron's or Hero's formula for area of scalene triangle worksheet, students solve 4 word problems using the formula given for area of a triangle.
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Worksheet
Curated OER

Trigonometry Worksheet

For Students 10th - 12th
In this trigonometry worksheet, students use the law of sines to find the length of a missing side of a triangle. They prove trigonometric identity and use Heron's formula to find the area of a triangle. This two-page worksheet...
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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.
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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.
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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.
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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.
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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.
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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.
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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....
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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Handout
Wolfram Research

Wolfram Math World: Area

For Students 9th - 10th Standards
Definitions and formulas for the computation of surface areas of triangles, rectangles, and any regular polygon. Helpful links to related pages.
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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...