Geometry: Incenter, Incircle, Inradius of a triangle, Theorems and Problems.

Problem 1341.
Isosceles Triangle, 80-20-80 Degrees, Circumcenter, Angle Bisector.

Geometry Problem 1374.
Isosceles Triangle, Exterior Cevian, Incircle, Excircle, Tangency Points, Parallel Lines.

Geometry Problem 1373.
Isosceles Triangle, Exterior Cevian, Inradius, Exradius, Altitude to the Base.

Geometry Problem 1372.
Equilateral Triangle, Exterior Cevian, Inradius, Exradius, Altitude, Sketch, iPad Apps.

Geometry Problem 1351.
Two Tangential or Circumscribed Quadrilaterals, Midpoints, Perpendiculars.

Geometry Problem 1350.
Triangle with three Intersecting Circles, Incircle, Collinear Points.

Geometry Problem 1346.
Equilateral Triangle, Point on the Incircle, Altitude, Perpendicular, Sum of Squares, Distance.

Problem 1340.
Triangle, Incenter, Concentric Circles, Isosceles Triangles, Congruence.

Geometry Problem 1326.
Triangle, Cevian, Incenters, Sum of Angles, 270 Degrees.

Geometry Problem 1320.
Triangle, Incircle, Tangent, Chord, Circle, Parallel, Perpendicular, Collinearity.

Geometry Problem 1316.
Triangle, Incircle, Tangent, Chord, Midpoint, Sum of two Segments, Congruence.

Geometry Problem 1315.
Triangle, Incircle, Tangent, Chord, Circle, Congruence.

Geometry Problem 1314.
Equilateral Triangle, Incircle, Inscribed Circle, Tangent, Congruence.

Geometry Problem 1309.
Triangle, Circle, Inradius, Excircle, Tangent, Exradius, Measurement.

Geometry Problem 1308.
Quadrilateral, Diagonal, Triangle, Incircle, Tangent Line, Sides, Measurement.

Geometry Problem 1307.
Triangle, Incenter, Parallel line, Sides, Measurement.

Geometry Problem 1304.
Triangle, 120 Degrees, Angle Bisector, Measurement.

Geometry Problem 1301.
Arbelos, Semicircles, Diameters, Circle, Incircle, Incenter, Square, Midpoint, Concurrency.

Geometry Problem 1300.
Arbelos, Semicircles, Diameters, Circle, Incircle, Tangent, Perpendicular, Concurrent Lines.

Geometry Problem 1298.
Arbelos, Semicircles, Diameters, Circle, Incircle, Tangent, Angle Bisector, Perpendicular, Midpoint.

Geometry Problem 1297.
Arbelos, Semicircles, Diameters, Tangent, Circle, Incircle, Angle Bisector.

Geometry Problem 1295.
Right Triangle, Incenter, Incircle, Excenter, Excircle, Congruence, Angle.

Geometry Problem 1292.
Square, Circle, Right Triangle, Arc, Inradius, Radius, Incircle, Measurement.

Geometry Problem 1288.
Triangle, 30-50-100 Degrees, Area, Inradius, Metric Relations, Measurement.

Geometry Problem 1274.
Isosceles Triangle, 80-20-80 Degrees, Area, Inradius, Circumradius, Angle Bisector, Metric Relations, Measurement.

Geometry Problem 1271.
Triangle, Incircle, Incenter, Excircle, Excenter, Escribed Circle, Tangency Points, Six Concyclic Points.

Geometry Problem 1269.
Triangle, Incircle, Incenter, Inscribed Circle, Tangency Points, Perpendicular, 90 Degrees, Angle Bisector.

Geometry Problem 1267.
Triangle, Incircle, Excircle, Circle, Tangency Points, Perpendicular, 90 Degrees, Parallelogram.

Geometry Problem 1265.
Triangle, Incircle, Circle, Tangency Points, Perpendicular, 90 Degrees, Angle Bisector.

Geometry Problem 1231
Triangle, Orthocenter, Incenter, Circumcenter, Angle Bisector, Center, Circle.

Geometry Problem 1217
Triangle, Circle, Excenter, Incenter, Angle Bisector, Cyclic Quadrilateral, Circumcircle, Tangent Line.

Geometry Problem 1207
Triangle, Circle, Incenter, Circumcenter, Excenter, Circumradius, Perpendicular, 90 Degrees.

Geometry Problem 1206
Circle, Angle Bisector, Secant, Triangle, Circumcircle, Congruence, Area.

Geometry Problem 1203
Right Triangle, Square, Angle Bisector, Three Congruent Quadrilaterals.

Geometry Problem 1191
Circle, Chords, Diameter, Congruence, Midpoint, Collinearity, Bisector.

Geometry Problem 1180
Quadrilateral, 120 Degrees, Diagonals, Perpendicular.

Geometry Problem 1178
Triangle, Angle Bisector, Metric Relations.

Geometry Problem 1177
Triangle, Two Angle Bisectors, Metric Relations.

Geometry Problem 1164.
Triangle, Angle Bisector, Cevian.

Geometry Problem 1174
Triangle, Quadrilateral, Double, Triple, Angle, Congruence, Excenter, Angle Bisector.

Geometry Problem 1163.
Isosceles Triangle, Congruence, Double Angle, Circle, Concyclic Points, Circumcenter, Perpendicular, Angle Bisector.

Geometry Problem 1153.
Triangle, Angle Bisectors, Perpendicular, Congruence.

Geometry Problem 1144.
Three Equal Squares, Diagonals, Perpendicular, 90 Degrees, Angle Bisector.

Geometry Problem 1139.
Triangle, Circumcircle, Angle Bisector, Parallel Lines, 90 Degrees, Concurrent Lines.

Geometry Problem 1199
Equilateral Triangle, Square, Altitude, Circle, Incircle, Inradius, Metric Relations.

Geometry Problem 1181
Cyclic Quadrilateral and Tangential Quadrilateral, Diameter as a Diagonal, Incenter, Circumcenter.

Geometry Problem 1155.
Right Triangle, Altitude, Incenter, Incircle, Area.

Geometry Problem 1149.
Isosceles Triangle, Altitude, Cevian, Incircles, Tangent, Congruence.

Dynamic Geometry Problem 1148
Static Geometry Problem 1148.
Right Triangle, Incircle, Circumcircle, Tangent, Radius. GeoGebra, HTML5 Animation for Tablets (iPad, Nexus).

Geometry Problem 1129.
Isosceles Triangle, Circumcenter, Incenter, Parallel Lines, Perpendicular Lines.

Geometry Problem 1105.
Triangle, Incircle, Excircle, Cevian, Tangent, Congruence, Geometric Mean.

Geometry Problem 1104.
Right Triangle, Incircle, Circumcircle, Inscribed Circle, Radius, Tangent.

Geometry Problem 1103.
Right Triangle, Incircle, Inscribed Circle, Radius, Geometric Mean, Sangaku, Japanese, Metric Relations.

Geometry Problem 1102.
Right Triangle, Incircle, Tangency Point, 90 Degree, Cathetus, Metric Relations.

Geometry Problem 1101.
Triangle, Parallel Lines, Circle, Incircle, Inradius, Radius, Angle.

Geometry Problem 1081.
Equilateral Triangle, Inscribed Circle, Inradius, Tangent Circles, Radius, Tangent Line, Sangaku Japanese Problem.

Geometry Problem 1068.
Obtuse Triangle, Orthocenter, Circumradius, Inradius, Exradii, Distance, Diameter

Geometry Problem 1067.
Acute Triangle, Orthocenter, Circumradius, Inradius, Exradii, Distance, Diameter.

Geometry Problem 1066.
Triangle, Obtuse Angle, Orthocenter, Circumradius R, Inradius r, Exradius r_a, Distance, Diameter.

Geometry Problem 1065.
Triangle, Acute Angle, Orthocenter, Circumradius R, Inradius r, Exradius r_a, Distance, Diameter.

Geometry Problem 1061.
Triangle, Inradius (r), Circumradius (R), Circumcircle, Angle Bisector, Distance from a point to a Line, Perpendicular.

Geometry Problem 1060.
Triangle, Incircle, Incenter, Inscribed circle, Tangent, Angle.

Geometry Problem 1043.
Right Triangle, Incenter, Excenter, Congruence, Metric Relations.

Geometry Problem 1037.
Triangle, Three equal Incircles, Tangent lines, Inradius, Length.

Geometry Problem 1036.
Triangle, Three equal Incircles, Tangent lines, Inradius, Equal Inradii.

Geometry Problem 1035.
Triangle, Three equal Incircles, Tangent lines, Equivalent triangles, Equal area.

Geometry Problem 1034.
Triangle, Three equal Incircles, Tangent lines, Isoperimetric triangles, Equal perimeter.

Geometry Problem 1024.
Contact, Gergonne Triangle, Point on an arc of Incircle, Perpendicular, Distances.

Geometry Problem 1023.
Triangle, Contact, Gergonne, Product of three distances.

Geometry Problem 1012.
Equilateral Triangle, Incenters, Inscribed Circles, Perpendicular, Concurrent Lines.

Geometry Problem 991.
Triangle, Incircle, Tangency Points, Isosceles, Midpoint, Collinearity, Congruence, Circle.

Geometry Problem 990.
Triangle, Incircle, Median, Cevian, Central Angle, Congruence, Circle, Secant, Midpoint, Parallel.

Geometry Problem 987.
Triangle, Circumcircle, Incenter, Chord, Parallel, Circle, Tangent. GeoGebra, HTML5 Animation for Tablets (iPad, Nexus).

Geometry Problem 976.
Isosceles Right Triangle, 45 Degrees, Incenter, Angle Bisector, Hypotenuse.

Geometry Problem 959.
Triangle, Sides Ratio 4:1, Inradius, Exradius, Cevian, Mean Proportional, Geometric Mean, Metric Relations.

Geometry Problem 957.
Equilateral Triangle, Inscribed Circle, Incircle, Circumscribed Circle, Circumcircle, Area, Circular Segment.

Geometry Problem 952.
Triangle, Incenter, Circumcenter, Three Equal Circles, Tangent Line, Tangent Circles, Collinear Points.

Geometry Problem 943.
Triangle, Incircle, Inscribed Circle, Tangency Points, Parallel, Metric Relations.

Geometry Problem 942.
Triangle, Circles, Circumcircle, Sagitta, Incircle, Excircle, Inradius, Exradius, Metric Relations.

Geometry Problem 935.
Square, Circle, Center, Perpendicular, Metric Relations.

Geometry Problem 921.
Right Triangle, Circumcircle, Arc, Midpoint, Tangency Point, Incircle.

Geometry Problem 918.
Triangle, Incenter, Incircle, Angle Bisector, Perpendicular, Metric Relations.

Geometry Problem 895
Triangle, Incircle, Tangency Points, Parallel line, Collinear Points.
GeoGebra, HTML5 Animation for Tablets

Geometry Problem 894
Triangle, Angle, 60 degrees, Incenter, Midpoint, Parallel Lines.
GeoGebra, HTML5 Animation for Tablets

Geometry Problem 893
Triangle, Circumcircle, Incenter, Circle, Tangent, Collinear Points.
GeoGebra, HTML5 Animation for Tablets

Geometry Problem 889
Carnot's Theorem in an acute triangle, Circumcenter, Circumradius, Inradius. GeoGebra, HTML5 Animation for Tablets.

Geometry Problem 886
Right Triangle, Incenter, Angle Bisector, Perpendicular, 45 Degrees, Concyclic Points, Isosceles Right Triangle. GeoGebra, HTML5 Animation for Tablets (iPad, Nexus).

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