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.
Khan Academy
Khan Academy: Area of Triangles
In this exercise, students practice finding the area of triangles. Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly.
Khan Academy
Khan Academy: Area of Triangles
Practice finding the area of right, acute, and obtuse triangles. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Khan Academy
Khan Academy: Areas of Shapes on Grids
In this exercise, students practice finding the areas of shapes on grids. Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly.
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....
Texas Instruments
Texas Instruments: Triangulation Problem
In this Computer Algebra System (CAS) activity, students use 'landscape' paper and fold the top left corner of the page so that it just touches the bottom of the page. They calculate the area of the triangle formed by the bottom left...
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
Calculator Soup
Calculator Soup: Isosceles Triangles Calculator
Use this calculator to find the sides, perimeter, area, semiperimeter, and altitude of an isosceles triangle.
University of Cambridge
University of Cambridge: Nrich: Disappearing Square
This one page website explains how to find the area of a triangle with an interactive graphic. It then offers a challenge. The solution is available right at the website.
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...
ClassFlow
Class Flow: Review of Area
[Free Registration/Login Required] This flipchart is a review of calculating the area of squares, rectangles, and triangles for fifth graders. It also includes problems that work backwards from the area to find missing dimensions. It...
Ducksters
Ducksters: Kids Math: How to Find Surface Area
Learn how to find the surface area of various shapes square, rectangle, and triangle on this website.
ClassFlow
Class Flow: Surface Area
[Free Registration/Login Required] In this lesson students learn how to find surface area of rectangular and triangular solids.
Maths Challenge
Maths challenge.net: Maximum Square
A challenging proof like geometry of finding the square inscribed in a triangle.
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.
Purple Math
Purplemath: Determinant Word Problems
Matrix determinants can be used to solve many algebra and geometry word problems. Among them: finding the area of a triangle, finding the area of a parallelogram, and finding the equation of a line between two points. These three...
Math Open Reference
Math Open Reference: Volume of a Triangular Prism
Use this interactive tool to find the volume of a triangular prism. Try different figures for the height and the dimensions of the triangular face to see how these affect the volume. An accompanying chart also presents five methods for...
CK-12 Foundation
Ck 12: Trigonometry: Heron's Formula
[Free Registration/Login may be required to access all resource tools.] Find the area of a triangle when all three sides are known.
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...
Calculator Soup
Calculator Soup: Right Triangles Calculator
Use this calculator to find the unknown angles in a right triangle using the Pythagorean Theorem. Once you know the sides you can calculate the perimeter, semiperimeter, area, and the altitudes.
Illustrative Mathematics
Illustrative Mathematics: 6.g Polygons in the Coordinate Plane
The purpose of this task is for students to practice plotting points in the coordinate plane and finding the areas of polygons. This task assumes that students already understand how to find areas of polygons by decomposing them into...
Other
Algebra Lab: Areas and Perimeters of Triangles and Special Quadrilaterals
Learn how to find the areas and perimeters of triangles and special quadrilaterals.