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Willow Tree
Area of Common Geometric Figures
Scholars can use area formulas, but can they apply what they know about area? The lesson challenges learners to think logically while practicing finding area of shapes such as rectangles, circles, parallelograms, triangles, and other...
Willow Tree
Surface Area of Three-Dimensional Figures
Lateral area and surface area are simple concepts, but calculating them is not as easy! Using formulas, learners calculate lateral area and surface area for the same three-dimensional figures. The resource discusses the formula variables...
Charleston School District
Applications of the Pythagorean Theorem
Use patterns to your advantage! The Pythagorean Theorem allows learners to find missing sides of right triangles. Problems include those with both rational and irrational lengths.
Willow Tree
Perimeter of Common Geometric Figures
Help learners understand that perimeter and circumference are one in the same. Learners apply their skills to determine the perimeter/circumference of triangles, rectangles, and circles. They then use the same strategy to find the...
Curated OER
Math Handbook: Trigonometry
You'll be spinning in unit circles once you read through this jumbo-sized resource of everything you need to know about trigonometry. Each page has color-coded examples with explicit directions that detail the problems and...
Charleston School District
Pythagorean Theorem and Converse
You've heard that it is true, but can you prove it? Scholars learn the Pythagorean Theorem through proof. After an overview of proofs of the theorem, learners apply it to prove triangles are right and to problem solve. This is the second...
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...
Math Open Reference
Math Open Reference: Volume of a Triangular Prism
A complete reference guide to finding the volume of a triangle prism. It provides definitions, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
Math Is Fun
Math Is Fun: Area of Triangles Without Right Angles
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.
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...
Calculator Soup
Calculator Soup: Isosceles Triangles Calculator
Use this calculator to find the sides, perimeter, area, semiperimeter, and altitude of an isosceles triangle.
Wolfram Research
Wolfram Math World: Midpoint
This MathWorld site offers a lesson on finding the midpoint of a line segment using a compass and finding the midpoint of the sides of a triangle. This site also has an interesting way of drawing two triangle with equal area by finding...