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This postulate helps us compare congruent triangles. We'll get to Einstein's postulates regarding special relativity and inertial frames of referen...

This video is sort of a PSA for SAS, ASA, and AAS. This stuff might show up on the ACT, so watch it ASAP.

As you'll see, we use cats' ears to explore the congruency of various triangles. Oh, calm down and stop dialing the the Humane Society. They're sti...

SAT Math 9.2 Geometry and Measurement

SAT Math 6.3 Geometry and Measurement

Use the area formula to solve for length of the base of the triangle.

SAT Math 10.4 Geometry and Measurement. What is the perimeter of triangle DEF?

SAT Math 5.5 Geometry and Measurement

This video explains similar figures and how to figure out if two shapes are similar using sides and angles. Plus, it discusses how to use one shape...

This video explains the vertical angle theorem. Learn about supplementary angles, adjacent angles, and linear pairs, plus bungee jumping. Intersect...

Sine is the opposite over the hypotenuse; cosine is the adjacent over the hypotenuse; and tangent is the opposite side over the adjacent side....

The triangle inequality theorem states that no two sides, when added, can be less then the length of the third side. However, that doesn't stop our...

This video covers the different types of triangle. What makes a triangle isosceles, scalene, or equilateral? What about the different kinds of angl...

SAT Math 2.5 Geometry and Measurement

SAT Math 3.5 Geometry and Measurement