Socratica
Sum of the Angles in a Triangle
You know that triangles have angle sums of 180 degrees, but can you prove it? A brief video in the Socratica Geometry series highlights an informal geometric proof. It shows that the sum of the interior angles of a triangle is 180...
Khan Academy
Khan Academy: Logarithm Properties: Change of Base Formula Proof
Explore logarithm properties through change of base formula proofs.
Sophia Learning
Sophia: Language of Geometry
This video lesson defines and provides an example of common geometry terms including theorem, postulate, axiom, and corollary.
Sophia Learning
Sophia: Counterexamples: Lesson 4
This lesson will help a learner understand counterexamples. It is 4 of 7 in the series titled "Counterexamples." [3:05]
Sophia Learning
Sophia: Mathematical Induction: Lesson 3
This lesson defines and demonstrates the principle of mathematical induction, and applies it to an example. It is 3 of 4 in the series titled "Mathematical Induction."
Sophia Learning
Sophia: Mathematical Induction: Lesson 4
This lesson defines and demonstrates the principle of mathematical induction, and applies it to an example. It is 4 of 4 in the series titled "Mathematical Induction."
Sophia Learning
Sophia: Methods of Proof: Lesson 2
In this lesson, students are introduced to different ways to prove an answer. It is 2 of 6 in the series titled "Methods of Proof."
Sophia Learning
Sophia: Mathematical Induction: Lesson 2
This lesson defines and demonstrates the principle of mathematical induction, and applies it to an example. It is 2 of 4 in the series titled "mathematical induction."
Sophia Learning
Sophia: Language of Geometry
This video tutorial introduces some common terms for geometry including axiom, postulate, theorem, and corollary. Students can check their understanding with an assessment.
Sophia Learning
Sophia: Methods of Proof: Lesson 6
In this lesson, students are introduced to different ways to prove an answer. It is 6 of 6 in the series titled "Methods of Proof."