Khan Academy
Khan Academy: Pythagorean Theorem Challenge
In this exercise, students practice using the Pythagorean Theorem in word problems. Students receive immediate feedback and have the opportunity to watch a video, get hints, or try questions repeatedly.
Math Planet
Math Planet: Pre Algebra: The Pythagorean Theorem
Learn all about the Pythagorean Theorem by viewing examples and a video lesson.
CK-12 Foundation
Ck 12: Interactive Geometry: 1.7 the Pythagorean Theorem
Explore and discover the Pythagorean theorem.
Varsity Tutors
Varsity Tutors: Hotmath: The Pythagorean Theorem
Twenty problems cover various aspects of the Pythagorean Theorem. They are given with each step to the solution cleverly revealed one at a time. You can work each step of the problem then click the "View Solution" button to check each...
Illustrative Mathematics
Illustrative Mathematics: F Tf Trigonometric Ratios and the Pythagorean Theorem
The purpose of this task is to use the Pythagorean Theorem to establish a fundamental trigonometric identity for an acute angle. The reasoning behind this identity is then applied to calculate a cosine for a given obtuse angle. Aligns...
Illustrative Mathematics
Illustrative Mathematics: 8.g Pythagorean Theorem in Mathematical Context
Eighth graders are shown a drawing of a rectangle with a central triangle bordered by three right triangles. They are asked to prove whether or not the middle triangle is also a right triangle. Aligns with 8.G.B.
Mathigon
Mathigon: Geometry: Triangles and Trigonometry: Pythagoras' Theorem
Pythagoras' Theorem: In any right-angled triangle, the square of the length of the hypotenuse (the side that lies opposite the right angle) is equal to the sum of the squares of the other two sides. (A+B=C)
Shodor Education Foundation
Shodor Interactivate: Squaring the Triangle
Students explore the relationship between the Pythagorean Theorem and right triangles. Teacher resources are included.
Illustrative Mathematics
Illustrative Mathematics: G Gpe Squares on a Coordinate Grid
The purpose of this task is to use the Pythagorean Theorem and knowledge about quadrilaterals in order to construct squares of different sizes on a coordinate grid. Aligns with G-GPE.B.7.
Illustrative Mathematics
Illustrative Mathematics: F Tf Special Triangles 1
Using known facts about the unit circle and isosceles triangles together with the Pythagorean Theorem, students can derive the sine and cosine of special angles. Aligns with HSF-TF.A.3.
Illustrative Mathematics
Illustrative Mathematics: F Tf Special Triangles 2
Using known facts about the unit circle and isosceles triangles together with the Pythagorean Theorem, students can derive the sine and cosine of special angles. Aligns with HSF-TF.A.3.
Illustrative Mathematics
Illustrative Mathematics: 8.g a Rectangle in the Coordinate Plane
In this task, 8th graders are shown a picture of a quadrilateral on a coordinate grid and are asked to use the Pythagorean Theorem to find lengths and to explain why the quadrilateral is a rectangle. Aligns with 8.G.B.
Illustrative Mathematics
Illustrative Mathematics: 8.g Area of a Trapezoid
Eighth graders are given various dimensions of a trapezoid and are asked to find its area. This requires them to use the Pythagorean Theorem and to decompose the trapezoid into other polygons. Aligns with 8.G.B.7.
World History Encyclopedia
World History Encyclopedia: Greek Mathematics
Discusses the major cultural influences on the development of mathematics in ancient Greece, and how the Greeks went on to surpass those cultures. The work of the Pythagoreans and of Euclid are described, along with some famous...
CK-12 Foundation
Ck 12: Trigonometry: Lengths of Sides in Isosceles Right Triangles
[Free Registration/Login may be required to access all resource tools.] Here you'll learn what an isosceles right triangle is, the relationships between the sides of an isosceles right triangle, and how to find the length of an unknown...
Khan Academy
Khan Academy: Distance Formula
Review how to derive a general formula for the distance between two points.
Other
Platonic Realms: Conics
This resource provides in depth information on the conic sections. Click on the underlined words for definitions and diagrams.
Illustrative Mathematics
Illustrative Mathematics: G C, G Srt Neglecting the Curvature of the Earth
Jerry and Ashley are trying to find out if it is possible to see the lowest point in the USA from the highest point in the USA. It turns out that the highest point in the United States, the peak of Mount Whitney, is only 85 miles from...
Illustrative Mathematics
Illustrative Mathematics: 8.g, G Gpe, G Srt, G Co Is This a Rectangle?
For this task, students are given four sets of coordinate pairs and are asked to determine if they represent a rectangle. Aligns with 8.G.A, 8.G.B, G-CO.B, G-GPE.B, and G-SRT.B.5.
Illustrative Mathematics
Illustrative Mathematics: G Srt, G Mg How Far Is the Horizon?
Some friends are at the beach looking out onto the ocean on a clear day and they wonder how far away the horizon is. A second problem asks how far the horizon would be from the top of a mountain. Students must also answer a question...
Illustrative Mathematics
Illustrative Mathematics: 8.g Bird and Dog Race
For this race between a bird and a dog, 8th graders are provided with information about their starting locations on a map and their speeds. They are asked to predict a winner, draw the paths they might follow, decide how to determine who...
Cut the Knot
Cut the Knot!: The Law of Cosines (Cosine Rule)
This site from Cut The Knot provides an overview of the law of cosines, complete with an explanation of the law and a proof of the law.