Triangles: Theorems and Problems 12

Geometry Problem 685
Isosceles Triangle, 100-40-40 Degrees, Angles, Congruence.

Geometry Problem 684: Outer Nagel Point.
Triangle, Excircles, Incircle Tangency points, Concurrent lines, Semi-perimeter, Ceva theorem.

Geometry Problem 683: Nagel Point.
Triangle, Excircles, Tangency points, Concurrent lines, Semi-perimeter, Ceva theorem.

Geometry Problem 682: Gergonne External Point.
Triangle, Excircle, Tangency points, Concurrent lines, Semiperimeter, Ceva theorem.

Geometry Problem 681: Gergonne Point.
Triangle, Incircle, Tangency points, Concurrent lines, Semiperimeter, Ceva theorem.

100 Geometry Problems Collection

Geometry Problem 679.
Triangle, Circle, Median, Proportion.

Geometry Problem 678.
Triangle, Simson Line, Circumcircle, Tangent, Parallel, Perpendicular, Collinear Points.

Geometry Problem 674.
Triangle, Altitude, Angles.

Geometry Problem 673.
Internally tangent circles, Chord, Tangent, Metric Relations.

Geometry Problem 671.
Triangle, Cevian, Angles, Congruence.

Geometry Problem 670.
Triangle, 60 Degrees, Orthocenter, Incenter, Circumcenter, Congruence.

Geometry Problem 669.
Triangle, Circumcircle, Incenter, Midpoint, Collinear points, Mind Map.

Geometry Problem 668.
Right triangle, Incircles, Parallel, Common Tangent, Mind Map.

Geometry Problem 664.
Triangle, 60 Degrees, Orthocenter, Incenter, Circumcenter, Angles, Triangle centers.

Geometry Problem 663.
Scalene Triangle, 60 Degrees, Altitude, Angle Bisector, Perpendicular Bisector, Concurrent lines.

Geometry Problem 662.
Triangle, Incenter, Circumcenter, Orthocenter, Circle, Angle, Measurement.

Geometry Problem 660.
Triangle, Circle, Diameter, Perpendicular Lines.

Geometry Problem 658.
Triangle, Altitudes, Diameter, Circle, Angles.

Geometry Problem 657.
Triangle, Incircle, Tangency Points, Parallel Lines, Congruence.

Geometry Problem 656.
Triangle, Cevian, Concurrent Lines.

Geometry Problem 633
Triangle, Parallel Lines, Intersecting Lines.

Geometry Problem 632.
Triangle, Interior and Exterior Angle Bisectors, Midpoints, Collinear Points.

Geometry Problem 631.
Triangle, Exterior Angle Bisectors, Collinear Points.

Geometry Problem 630: Clawson Point.
Orthic and Extangents Triangles, Concurrent lines.

Geometry Problem 629
Triangle, Perpendicular to Sides, Intersecting Lines, Altitude.

Geometry Problem 626
Triangle, Distance from the Incenter to an Excenter.

Geometry Problem 625
Triangle, Parallel Lines, Congruence, Angle Bisector.