Khan Academy on a Stick
Congruent triangles
If you can take one figure and flip, shift and rotate (not resize) it to be identical to another figure, then the two figures are congruent. This topic explores this foundational idea in geometry.

Congruent Triangles and SSS
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What it means for triangles to be congruent

SSS to Show a Radius is Perpendicular to a Chord that it Bisects
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More on the difference between a theorem and axiom. Proving a cool result using SSS

Other Triangle Congruence Postulates
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SSS, SAS, ASA and AAS postulates for congruent triangles. Showing AAA is only good for similarity and SSA is good for neither

Two column proof showing segments are perpendicular
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Using triangle congruency postulates to show that two intersecting segments are perpendicular

Finding Congruent Triangles
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Using the SSS, ASA, SAS, and AAS postulates to find congruent triangles

More on why SSA is not a postulate
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SSA special cases including RSH

Perpendicular Radius Bisects Chord
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Simple proof using RSH postulate to show that a radius perpendicular to a chord bisects it

Congruent Triangle Proof Example
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Proving that a point is the midpoint via triangle congruency

Congruent Triangle Example 2
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Showing that segments have the same length
Congruence postulates
We begin to seriously channel Euclid in this tutorial to really, really (no, really) prove thingsin particular, that triangles are congruents. You'll appreciate (and love) what rigorous proofs are. It will sharpen your mind and make you a better friend, relative and citizen (and make you more popular in general). Don't have too much fun.

Congruent legs and base angles of Isosceles Triangles
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Showing that congruent legs imply equal base angles and vice versa

Equilateral Triangle Sides and Angles Congruent
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Showing that all of the angles of an equilateral triangle are 60 degrees

Equilateral and Isosceles Example Problems
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Three example problems involving isosceles and equilateral triangles. 2 from Art of Problem Solving (by Richard Ruscyk) book

Another Isosceles Example Problem
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Possible angles for an isosceles triangle

Example involving an isosceles triangle and parallel lines
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Integrating what we know about isosceles triangles and parallel lines

Figuring out all the angles for congruent triangles example
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Another example of using congruency to figure out a bunch of angles

Problem involving angle derived from square and circle
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Challenging problem to find an angle
Congruence and isosceles and equilateral triangles
This tutorial uses our understanding of congruence postulates to prove some neat properties of isosceles and equilateral triangles.