CK-12 Foundation
Ck 12: Interactive Geometry: 1.7 the Pythagorean Theorem
Explore and discover the Pythagorean theorem.
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.
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)
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...
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.
Khan Academy
Khan Academy: Distance Formula
Review how to derive a general formula for the distance between two points.
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.