Professor Dave Explains
Proving the Pythagorean Theorem
One easy demonstration that proves the validity of the Pythagorean theorem.
Scholastic
Study Jams! Classify Triangles
Jam on with this multi-faceted activity teaching triangle classification. Start with a learner-paced lesson describing the different qualities of triangles and follow with a fun karaoke session. Also provided are two types...
Curated OER
Trigonometry Work Problems (Part 2)
In this part two video, Sal finishes the trigonometric word problem of the wayward ship captain. He wisely continues the algebra work on the problem before finally turning to his calculator for the very last calculation.
Khan Academy
Trigonometry Word Problems (Part 1)
Sal starts to solve a trigonometric word problem of a wayward ship captain who veers off course and once aware of his predicament, needs to know how far he is from his destination. Instead of using the Law of Cosines in his solution, Sal...
Khan Academy
Ferris Wheel Trig Problem
The next time you are at an amusement park you may want to consider all the interesting math problems you could do! Using trigonometric ratios, some logic and algebra, Sal solves a problem in this video of finding a person's height off...
Curated OER
Trigonometry work problems (part 2)
In this part 2 video, Sal finishes the trigonometric word problem of the wayward ship captain. He wisely continues the algebra work on the problem before finally turning to his calculator for the very last calculation.
Khan Academy
SAT Prep: Test 1 Section 9 Part 3
If it takes a long time to complete the problems on the math SAT, it doesn't matter if they are correct - the problems that are left over will count against the student's score. Sal takes care to show quicker ways to complete problems...
Flipped Math
Unit 7 Review: Right Triangles
It is all right to spend some time with a review. After watching a short review video covering the materials from the unit, pupils work through 23 review problems. Scholars work on problems involving the Pythagorean Theorem and its...
Flipped Math
Special Right Triangles II
Show students that right triangles are radical. Learners see how the lengths of the sides of a 45-45-90 triangle relate. Using that relationship, pupils observe how to find any of the lengths given one side of a triangle. They go on to...
Flipped Math
Special Right Triangles I
Introduce a special relationship with right triangles. Learners discover the ratio of the sides in a 30-60-90 triangle. After watching several examples and seeing two different methods, pupils find unknown sides in triangles. Scholars...
Flipped Math
CPCTC and HL Theorem
The resource is sure to be a right fit for introducing the congruence of right triangles. The fourth of five lessons in the Geometry - Triangle Congruence unit teaches pupils how to use CPCTC to prove congruent parts. They also apply the...
Flipped Math
Triangles
Take time to tackle triangles. Scholars watch a video that first reviews the types of triangles. They then investigate the Isosceles Triangle Theorem and see how to apply it to solve problems. At the end, individuals also learn how to...
TED-Ed
Can You Solve the Unstoppable Blob Riddle?
Viewers of an entertaining short video have an opportunity to save the world! All they have to do is solve the unstoppable blob riddle. Acute learners will have no problem with this problem.
Corbett Maths
Showing a Triangle Is Right Angled
Determine whether it is right or not. Using the Pythagorean Theorem, the video shows how to determine whether a triangle is a right triangle. Pupils practice the skill in a few of the problems in the associated worksheets on the...
Corbett Maths
Trigonometry – Missing Sides
If it's missing, then find it. Young mathematicians watch a video that explains how to solve for a missing side of a right triangle. They then complete a worksheet on the topic. The use of trigonometric ratios is expected here.
Corbett Maths
Trigonometry Introduction
Don't go off on a tangent. An instructive video describes how to find the sine, cosine, and tangent ratios of an angle in a right angle. It describes how to label the sides of a right triangle and how to use mnemonics to remember the...
Corbett Maths
Pythagoras
Even Pythagoras couldn't explain it better. Scholars watch an informative video that shows how to solve for missing sides of a right triangle using the Pythagorean Theorem. It covers four examples: two for finding the hypotenuse and two...
CK-12 Foundation
Inverse Trigonometric Ratios: Lesson
Finding the inverse of trigonometric ratios is not the same as finding the reciprocal. The presentation introduces how to find the angle of a right triangle given sides. Part of a larger playlist on geometry, the video uses the inverse...
CK-12 Foundation
Special Right Triangle 30-60-90: Lesson
It is special—given one length, you can find the other two. A segment of a basic geometry playlist provides the ratio of the lengths of sides of a 30-60 right triangle. The presentation shows how to use the ratio to find side lengths...
CK-12 Foundation
Special Right Triangle 45-45-90: Lesson
Square roots connect squares and right triangles. Using the Pythagorean Theorem, the video shows the relationship between the sides and hypotenuse of a 45-45 right triangle. The portion of a larger geometry playlist applies the...
CK-12 Foundation
Altitudes: Examples
Find the location of altitudes—from any elevation! The video presents the definition of an altitude of a triangle. By drawing examples, the segment of a larger geometry playlist highlights the location of altitudes of various triangle...
CK-12 Foundation
HL Triangle Congruence: Lesson
Use the right congruence statement. The video introduces the Hypotenuse-Leg Theorem to prove two right triangles are congruent. Part of a geometry playlist shows that it does not matter which leg to use when proving congruence.
CK-12 Foundation
The Trigonometric Ratios: Lesson
SOH, what is this thing called trigonometric ratios? A section of an extensive playlist on geometry identifies the adjacent and opposite sides in relationship of an angle. Using the identified sides, the video defines the sine, cosine,...