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![Geometry Problems, Online Education](../problem/h_geometry_problem_910.jpg)
Geometry Problems 681-690: Triangle, Incircle, Excircle, Ceva, Semiperimeter, Concurrency, Gergonne, Nagel Point
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![Gergonne Point Theorem](../geometry/p681_gergonne_point_in_1.jpg) |
Geometry Problem 681:
Gergonne Point.
Triangle, Incircle, Tangency points, Concurrent lines, Semiperimeter, Ceva theorem. |
![Gergonne Point Theorem](../geometry/p682_gergonne_point_ex_1.jpg) |
Geometry Problem 682: Gergonne External Point.
Triangle, Excircle, Tangency points, Concurrent lines, Semiperimeter, Ceva theorem. |
![Nagel Point](../geometry/p683_nagel_point_interior_1.jpg) |
Geometry Problem 683:
Nagel Point.
Triangle, Excircles, Tangency points, Concurrent lines, Semi-perimeter, Ceva theorem. |
![Outer Nagel Point](../geometry/p684_nagel_point_exterior_1.jpg) |
Geometry Problem 684:
Outer Nagel Point.
Triangle, Excircles, Incircle Tangency points, Concurrent lines, Semi-perimeter, Ceva theorem. |
![Isosceles triangl 100-40-40 degrees](../geometry/p685_isosceles_100_degree_1.jpg) |
Geometry Problem 685
Isosceles Triangle, 100-40-40 Degrees, Angles, Congruence. |
![Triangle, Excircles, Tangent](../geometry/p686_excircles_tangent_1.jpg) |
Geometry Problem 686.
Triangle, Three Excircles, Tangency points, Tangent lines, Semi-perimeter, Congruence. |
![Triangle, Excircles, COncurrency](../geometry/p687_triangle_excircles_1.jpg) |
Geometry Problem 687.
Triangle, Three Excircles, Tangency points, Concurrent Lines. |
![Geometry Problem 688, Triangle, 60 Degrees, Mind Map](../geometry/p688_triangle_60_degree_1.jpg) |
Geometry Problem 688.
Triangle, Angles, 10, 20, 30, 40, 60 Degrees, Measure, Mind Map, Polya. |
![Triangle, Excircles, Tangent, Concurrency](../geometry/p689_triangle_excircles_1.jpg) |
Geometry Problem 689.
Triangle, Three Excircles, Tangency points, Tangent lines, Concurrent Lines, Mind Map. |
![Distance between the incenter to the centroid](../center/distance_incenter_centroid_.jpg) |
Problem 690: Distance between the Incenter and the Centroid of a
Triangle.
Formula in terms of the sides a,b,c. |
![Geometry problems 691-700](geometry_problems_691_700_1.jpg)
![Geometry problems 671-680](geometry_problems_671_680_1.jpg) |
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