Triangles: Theorems and Problems 30
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![Triangles](../geometry/triangles_index_17.jpg) |
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![Elearn 127: Centroid, Incenter](../problem/p127_centroid_incenter_17.jpg) |
Proposed Problem
127. Centroid and Incenter of a Triangle,
Parallel, Proportions.
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![Elearn 126: Incenter Proportions](../problem/p126_incenter_proportion_17.jpg) |
Proposed Problem
126. Incenter of Triangle, Angle Bisector, Proportions.
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![Angle Bisector Theorem](../geometry/euclid_elements_vi_3_bisect.jpg) |
Euclid's Elements Book VI, Proposition 3: Angle Bisector Theorem |
![Pythagoras Theorem, 47th Proposition of Euclid's Book I](../pythagoras/pythagoras_euclid_theorem_170.jpg) |
The significance of the Pythagorean theorem by Jacob Bronowski.
Pythagorean Theorem, 47th Proposition of Euclid's
Book I. |
![Elearning 125: Area](../problem/p125_triangle_star_17.jpg) |
Proposed Problem
125. Area of Triangle, Star,
Trisection of Sides.
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![Elearning 124: Triangle Area, Similarity](../problem/p124_triangle_similarity_17.jpg) |
Proposed Problem
124. Area of triangle,
Similarity, Trisection of Sides.
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![Elearning 123: Triangle Similarity, Area](../problem/p123_triangle_similarity_17.jpg) |
Proposed Problem
123. Area of triangle,
Similarity, Trisection of Sides.
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![Marion Walter's Theorem](../problem/p122_marion_walter_proof_17.jpg) |
Proposed Problem
122. Marion Walter's Theorem.
Area of triangle and Hexagon, Trisection of Sides.
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![Elearning 121: Similarity and Area](../problem/p121_triangle_similarity_17.jpg) |
Proposed Problem
121. Similarity and Area
of triangle, Trisection of Sides.
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![Bottema Theorem. Elearning.](../geometry/bottema_theorem_elearning.jpg) |
Bottema's Theorem:
Triangle and Squares with Interactive
Geometry Software
Step-by-Step construction, Manipulation, and animation. |
![Complete quadrilateral: ortholine, Elearning](../geometry/quadrilateral_ortholine_17.jpg) |
Complete Quadrilateral: Ortholine-Steiner Line.
Step-by-Step construction, Manipulation, and animation |
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Proposed Problem
120. Area of triangle,
incenter, excircles,
tangent.
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![Elearn 119: Triangle area.](../problem/p119_area_triangle_incenter_17.jpg) |
Proposed Problem
119. Area of triangle,
incenter, excircle,
tangent.
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![Problem 118](../problem/p118_area_triangle_elearn_17.jpg) |
Proposed Problem
118. Area of triangle,
incenter, excenter,
tangent.
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