Euclid's Elements Book I, Proposition 8: (Side-Side-Side SSS Congruence)

If two triangles have the two sides equal to two sides respectively, and have also the base equal to the base, they will also have the angles equal which are contained by the equal straight lines.
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Euclid's Elements Book I, Proposition 8

Euclid's Elements Book I, Proposition 7

Given two straight lines constructed on a straight line (from its extremities) and meeting in a point, there cannot be constructed on the same straight line (from its extremities), and on the same side of it, two other straight lines meeting in another point and equal to the former two respectively, namely each to that has the same extremity with it.
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Euclid's Elements Book I, Proposition 7

Problem 428: Quadrant of a circle, Square, Angle bisector, Measurement

Proposed Problem
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Complete Problem 428

Level: High School, SAT Prep, College geometry

Problem 427: Triangle, Two Altitudes, Square of a Side

Proposed Problem
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Complete Problem 427

Level: High School, SAT Prep, College geometry

Euclid's Elements Book I, Proposition 6

If in a triangle two angles be equal to one another, the sides which subtend the equal angles will also be equal to one another.
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Euclid's Elements Book I, Proposition 6

Euclid's Elements Book I, Proposition 5: (Pons Asinorum)

In isosceles triangles the angles at the base are equal to one another, and, if the equal straight lines are produced further, then the angles under the base will be equal to one another.
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Euclid's Elements Book I, Proposition 5

Kaleidoscope based on Silents, 1988, 1966, 1998 by Roy Newell

Kaleidoscope
Exhibition: 'The Private Myth', Carolina Nitsch Project Room
This exhibition will introduce many people to the vehement, transcendent geometry of Roy Newell.
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Kaleidoscope based on Silents, 1988, 1966, 1998 by Roy Newell

The World's Most Innovative Companies 2010, Interactive Mind Map

Most Innovative Companies for 2010 ranked by Fast Company magazine.

Graphic organizers are visual representations of knowledge, concepts or ideas.
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The World's Most Innovative Companies 2010

Problem 426: Triangle, Circumradius, Circumcenter, concurrent Cevians

Proposed Problem
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Complete Problem 426

Level: High School, SAT Prep, College geometry

Geometry Problem 425: Quadrilateral, Triangle, Angles, 10, 20, 50 degrees, Congruence

Proposed Problem
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Complete Problem 425

Level: High School, SAT Prep, College geometry

Problem 424: Triangle, Cevian, Angle, 90 degree, Congruence

Proposed Problem
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Complete Problem 424

Level: High School, SAT Prep, College geometry

Euclid's Elements Book I, Proposition 4: SAS

If two triangles have two sides equal to two sides respectively, and have the angles contained by the equal sides also equal, then the two triangles are congruent
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Euclid's Elements Book I, Proposition 4

Euclid's Elements Book I, Proposition 3

Given two unequal straight lines, to cut off from the greater a straight line equal to the less
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Euclid's Elements Book I, Proposition 3

Euclid's Elements Book I, Proposition 2

To place at a given point (as an extremity) a straight line equal to a given straight line
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Euclid's Elements Book I, Proposition 2

Euclid's Elements Book I, Proposition 1

On a given finite line to construct an equilateral triangle
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Euclid's Elements Book I, Proposition 1

Problem 423: Triangle, 30, 40 degree, Angle, Congruence

Proposed Problem
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Level: High School, SAT Prep, College geometry