CK-12 Foundation
Ck 12: Trigonometry: Alternate Formula for the Area of a Triangle
[Free Registration/Login may be required to access all resource tools.] An alternate formula for the area of a triangle.
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.
Texas Instruments
Texas Instruments: Proof of the Pythagorean Theorem Using Transformations
In this activity, students will explore visual proofs of the Pythagorean Theorem using area and transformations. They will use the Cabri Jr. app to perform translations on the squares constructed on the two legs and the hypotenuse of a...
Khan Academy
Khan Academy: Use Area of Squares to Visualize Pythagorean Theorem
Apply the Pythagorean theorem and its converse to solve these problems. 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
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.
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.
Ministry of Education and Employment of Spain
Red Escolar: Un Triangulo Sorprendente
In Spanish. Different activities which involve the following concepts: right triangles, perpendicular lines, classification of triangles, area of a square and Pythagorean theorem.
Math Open Reference
Math Open Reference: Triangles
A complete reference guide to types of triangles and triangle perimeter and area. It provides definitions and interactive animated activities that enhance further explanation.
Louisiana Department of Education
Louisiana Doe: Louisiana Believes: Eureka Math Parent Guide: Area, Surface Area, and Volume Problems
A guide to support parents as they work with their students with area, surface area, and volume problems.
Khan Academy
Khan Academy: Use Pythagorean Theorem to Find Area and Perimeter
Find the area and perimeter of triangles and quadrilaterals by first using the Pythagorean Theorem to find missing side lengths. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video, or...
BBC
Bbc: Bitesize: Maths: 2 D Shapes
Learn about the properties of 2-D shapes: circles, triangles, polygons, and quadrilaterals. Includes information, video, and examples about each, with games and quizzes for reinforcement.
Curated OER
Educational Technology Clearinghouse: Maps Etc: New Hampshire, 1903
A map from 1903 of New Hampshire showing the capital of Concord, counties and county seats, principal cities and towns, railroads, rivers, and mountain ranges. "New Hampshire, one of the New England States of the American Union, lies...