Khan Academy
Khan Academy: Area & Perimeter on the Coordinate Plane
Find the area or perimeter of shapes like triangles, rectangles, parallelograms, and hexagons on the coordinate plane.
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...
Better Lesson
Better Lesson: Finding the Area of a Triangle
Sixth graders find the area of a triangle using square units and the area formula.
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.
CK-12 Foundation
Ck 12: Interactive Geometry: 17.5 Sine to Find the Area of a Triangle
Learn how to sine to find the area of a triangle.
CK-12 Foundation
Ck 12: Trigonometry: Introduction to the Triangle Area Formula
[Free Registration/Login may be required to access all resource tools.] This lesson covers how to find the area of a triangle using sine.
Khan Academy
Khan Academy: Find Missing Length When Given Area of a Triangle
Find the base or height of a triangle when given the other and the area. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
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...
Khan Academy
Khan Academy: Area of Right Triangles
Find the area of right triangles Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
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]
CK-12 Foundation
Ck 12: Geometry: Unknown Dimensions of Triangles Grade 6
[Free Registration/Login may be required to access all resource tools.] Find the unknown dimensions of a triangle given its area and another dimension.
Khan Academy
Khan Academy: Shaded Areas
Find the areas of shaded regions which are combinations of squares, triangles, and circles. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
National Council of Teachers of Mathematics
Nctm: Illuminations: Igd: Area of a Triangle
Use this interactive tool to learn how to find the area of a triangle. Click on "Instructions" for details on how to use this tool. Click on "Explore" for more ideas. [Requires Java.]
Oswego City School District
Regents Exam Prep Center: Area of a Triangle and Parallelogram Using Trig
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...
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.
Discovery Education
Discovery Education: Web Math: Find Out Things About a Right Triangle
Gives basic info about a right triangle. Also students can substitute values for sides or angles in order to find missing values. The method for solving is then explained.
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.
Sophia Learning
Sophia: Using Right Triangle Trigonometry to Find the Area of Regular Polygons
This lesson will demonstrate how to use right triangle trigonometry and special right triangles (45-45-90 and 30-60-90) to find the area of triangles given the side lengths of the polygon. It is 2 of 4 in the series titled "Using Right...
Sophia Learning
Sophia: Using Right Triangle Trigonometry to Find the Area of Regular Polygons
This lesson will demonstrate how to use right triangle trigonometry and special right triangles (45-45-90 and 30-60-90) to find the area of triangles given the side lengths of the polygon. It is 4 of 4 in the series titled "Using Right...
CK-12 Foundation
Ck 12: Determination of Unknown Triangle Measures Given Area
[Free Registration/Login may be required to access all resource tools.] Looks at triangle problems where you are given the area and must use trigonometry to find unknown sides or angles.
Khan Academy
Khan Academy: Find Base and Height on a Triangle
Identify the height of a triangle when given the base. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Illustrative Mathematics
Illustrative Mathematics: G C, G Srt Setting Up Sprinklers
In this task, students must decide where to place sprinklers on a lawn so that the maximum area of the lawn will be watered. To solve it, they must find areas of sectors of circles and use trigonometric ratios to solve right triangles....
CK-12 Foundation
Ck 12: Interactive Geometry: 1.6 Area or Perimeter of Triangles/ Quadrilaterals
Explore finding and measuring perimeter of figures.
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