Khan Academy
Khan Academy: Triangles: Another Isosceles Example Problem
Review possible angles for an isosceles triangle in this short video.
Khan Academy
Khan Academy: Triangles: Finding Congruent Triangles
This video uses the SSS, ASA, SAS, and AAS postulates to find congruent triangles.
Khan Academy
Khan Academy: Triangles: 30 60 90 Triangle Example Problem
Using what we know about 30-60-90 triangles to solve what at first seems to be a challenging problem in this short video.
Khan Academy
Khan Academy: Triangles: Triangle Angle Example 1
Explains how to use the triangle sum theorem to solve for missing angle measures in a triangle. A little about exterior angles being the sum of the remote interior angles. Also shows the relationship between the measure of an exterior...
Khan Academy
Khan Academy: Triangles: Median Centroid Right Triangle Example
This video demonstrates how to find various measures of triangles formed by the medians of a right triangle.
Khan Academy
Khan Academy: Triangles: Review of Triangle Properties
Provides a review of perpendicular bisectors, angle bisectors, medians, and altitudes and the special points of concurrency formed by these parts of a triangle.
Khan Academy
Khan Academy: Triangles: Circumcenter of a Triangle
Multiple proofs showing that a point is on a perpendicular bisector of a segment if and only if it is equidistant from the endpoints. Using this to establish the circumcenter, circumradius, and circumcircle for a triangle.
Khan Academy
Khan Academy: Triangle Angle Properties: Sum of Interior Angles of a Polygon
Students explore the interior angles of a polygon by explanding on the concept that a triangle has 180 degrees and developing a formula for all polygons.
Khan Academy
Khan Academy: Triangles: Congruent Triangle Proof Example
Students learn how to prove that two triangles are congruent using midpoint of line segments.
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Khan Academy: Triangles: Pythagorean Theorem 3
This video demonstrates how to solve the width of a rectangular carpet given the length and the diagonal of the rectangle by using the Pythagorean theorem.
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Khan Academy: Triangles: Area of an Equilateral Triangle
This video tutorial explores finding the formula for the area of an equilateral triangle with side length of s.
Khan Academy
Khan Academy: Triangles: Area of Inscribed Equilateral Triangle
Students explore a problem that requires then to figure out the area of an equilateral triangle inscribed in a circle using a little trigonometry.
Khan Academy
Khan Academy: Triangles: Circumcenter of a Right Triangle
The video tutorial shows that the midpoint of the hypotenuse is the circumcenter.
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Khan Academy: Triangles: Congruent Triangle Example 2
Students watch a video tutorial showing that segments have the same length using triangle congruence properties.
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Khan Academy: Triangles: Medians Divide Into Smaller Triangles of Equal Area
Showing that the three medians of a triangle divide it into six smaller triangles of equal area. Also a brief discussion of the centroid is given.
Khan Academy
Khan Academy: Doodling in Math: Doodling in Math: Triangle Party
Video exploring triangles and illustrating fractal concepts such as the Koch snowflake
Khan Academy
Khan Academy: Triangle Inequality Theorem: Triangle Inqequality Theorem
Review intuition behind the triangle inequality theorem in this short video.
Khan Academy
Khan Academy: Example Involving an Isosceles Triangle and Parallel Lines
This video demonstrates how to use the triangle sum theorem, properties of isosceles triangles, and special angle pairs formed when parallel lines are cut by a transversal to set up an equation using given algebraic expressions for angle...
Khan Academy
Khan Academy: Triangles: Similar Triangle Example Problems
Demonstration on how to determine if triangles are similar based on AA, SSS, or SAS similarity postulates.
Khan Academy
Khan Academy: Triangles: Congruent Triangles and Sss
This video tutorial explains how to use triangle congruence to identify measures of corresponding sides and angles in triangles. Defines side-side-side (SSS) postulate.
Khan Academy
Khan Academy: Triangles: Triangle Angle Example 2
Shows how to find the measure of missing angles using the triangle sum theorem and vertical angles.
Khan Academy
Khan Academy: Triangles: Pythagorean Theorem Proof Using Similarity
This video shows a proof for the Pythagorean Theorem by breaking a right triangle into two similar triangles and setting up ratios of corresponding sides.
Khan Academy
Khan Academy: Triangles: Pythagorean Theorem Ii
More Pythagorean Theorem examples. Introduction to 45-45-90 triangles.
Khan Academy
Khan Academy: Basic Triangle Proofs Module Example 2
A video proving that the given triangles are congruent by ASA.