Let's Tute
Circle Theorems: An Introduction
Circle Theorems part 1/3: In this video, the teacher breaks down the concept of theorems related to circles and provides a step-by-step explanation of 12 theorems. The teacher also covers basic concepts and terms related to circles and...
Curated Video
The Greeks and Proof
The Greek development of a rigorous system of logic and reasoning, which led to the first mathematical proofs. Maths - History Of Maths A Twig Math Film. Reinforce and extend the learning required by the curriculum. Twig’s context films...
Let's Tute
Introduction to Tangents in Circles
This is a video about tangents in circles, explaining what they are, how they get their name, and their properties. The video also includes examples and proofs to help understand the concepts better.
PBS
Can We Combine pi & e to Make a Rational Number?
Can you produce a rational number by exchanging infinitely many digits of pi and e?
Curated Video
AMAZING CIRCLE ILLUSION! Optical Illusion Explained With Math
This incredible optical illusion shows how circular motion can result from linear motion! The reason we see the circle has to do with high school geometry. I explain why and give a formal mathematical proof in the video. My blog post for...
Curated Video
VERY HARD South Korean Geometry Problem (CSAT Exam)
Thanks to Hyeong-jun (H. J.) for emailing me this problem! This is a challenging problem from the math section of the 1997 CSAT, a standardized test in South Korea. Can you figure it out? It took me several attempts, but it was really...
Brian McLogan
Use a Two Column Proof to Prove Two Triangles are Congruent - Congruent Triangles
👉 Learn how to prove that two triangles are congruent. Two or more triangles are said to be congruent if they have the same shape and size. There are many postulates and theorems to determine whether two triangles are congruent. They...
Brian McLogan
Writing a Two Column Proof to Prove Two Triangles are Congruent - Congruent Triangles
👉 Learn how to prove that two triangles are congruent. Two or more triangles are said to be congruent if they have the same shape and size. There are many postulates and theorems to determine whether two triangles are congruent. They...
Curated Video
A 16 Year Old Discovered This AMAZING Geometry Hidden Pattern. Pascal's Theorem
Pascal discovered this amazing geometry result when he was only 16. The book "The Art of the Infinite" by Robert Kaplan and Ellen Kaplan has a wonderful introduction to projective geometry and a proof this this theorem. Proof of Pascal's...
3Blue1Brown
Why is pi here? And why is it squared? A geometric answer to the Basel problem
A beautiful solution to the Basel Problem (1+1/4+1/9+1/16+...) using Euclidian geometry. Unlike many more common proofs, this one makes it very clear why pi is involved in the answer.
3Blue1Brown
Why is pi here? And why is it squared? A geometric answer to the Basel problem
A beautiful solution to the Basel Problem (1+1/4+1/9+1/16+...) using Euclidian geometry. Unlike many more common proofs, this one makes it very clear why pi is involved in the answer.
Curated Video
Speed of the Earth
Even when you are standing still, you are moving through space at incredible speed. Find out how to calculate just how fast the Earth is moving. Maths - Accuracy And Proof A Twig Math Film. Reinforce and extend the learning required by...
Curated Video
5 Facts You Should Know About Pi (Happy Pi Day!)
Happy Pi Day! At 3/14/15 at 9:26 the time will be accurate to pi for 7 decimal places. What's your favorite fact about pi? Links to proofs and more below in the description. 1. The definition 00:10 Related: the area of circle intuitive...
Curated Video
Genius Trick For A Devilishly Hard Math Problem - Sum Of 6s Puzzle
What is 6 + 66 + 666 + ... + 666...6? Each new number has one more digit equal to 6, and the last number has 666 digits of 6. Watch the video for a solution. My blog post for this video (includes 2 other solution methods):...
Curated Video
HARD Math Problem A 13 Year-Old Solved 1 Second! 2017 MathCounts Final Question
"In a barn, 100 chicks sit peacefully in a circle. Suddenly, each chick randomly pecks the chick immediately to its left or right. What is the expected number of unpecked chicks?" This question is from the 2017 Raytheon National...
Curated Video
GENIUS Test Divisibility By 7 - Graph Visualization
This graph will tell you if a number is divisible by 7. Start at the circle YES. Move a number of black arrows equal to the first (leftmost) digit of the number. Then move one green arrow to get to the next digit. Repeat this for each...
Corbett Maths
Radius and Tangent – Proof
A tangent line always finds its place at a 90-degree angle to a radius. Many scholars struggle with the proof of the seemingly simple statement. A brief video demonstrates the reasoning behind the proof before pupils practice applying it...
CK-12 Foundation
Angles Outside a Circle: Lesson
Understand the difference in finding angle measures. A segment of an extensive geometry playlist introduces the formula to find the measure of an angle formed outside of a circle. Using examples, the video shows how to calculate measures...
CK-12 Foundation
Inscribed Angles in Circles: Lesson
Circle the angles and intercept the arcs. The video introduces three theorems relating to inscribed angles in circles. Using drawings, the segment of a playlist on geometry illustrates the measure of angle along with theorems about two...
CK-12 Foundation
Chords in Circles: Lesson
Strike a chord with four theorems. The segment of a playlist on geometry introduces four basic theorems about chords in a circle. Theorems include the relationships between diameters and chords, congruent chords and arcs, and congruent...
CK-12 Foundation
Inscribed Quadrilaterals in Circles: Lesson
Find supplementary information about inscribed angles. A section of a large geometry playlist introduces the relationship of angles in an inscribed quadrilateral. The presentation works through examples that use the relationship between...
Khan Academy
Khan Academy: Geometry: Right Triangles Inscribed in Circles (Proof)
This video tutorial [5:35] explains that if the diameter of a circle is one of the sides of a triangle inscribed in the circle then the triangle is a right triangle. This video also appears in the strand Geometry: Circles.
Khan Academy
Khan Academy: Geometry: Inradius Perimeter and Area
Proof that the area of a triangle is equal to half the inradius times the perimeter of the triangle, or the area is equal to the inradius times the semiperimeter. This video also appears in the Geometry: Circles strand. [7:29]