Triangles: Theorems and Problems 15

Problem 564.
Complete Quadrilateral, Incenter, Excenter, Concyclic Points, Incircle, Excircle.

Problem 562.
Triangle, Cevian, Incenter, Perpendicular, Concyclic Points, Cyclic Quadrilateral.

Problem 561.
Triangle, Cevian, Incenter, Incircle, Perpendicular, Tangent.

Problem 560.
Triangle, Cevian, Incenter, Incircle, Perpendicular, Tangent.

Problem 559.
Triangle, Cevian, Incenters, Angle, 90 Degrees.

Problem 548.
Triangle, Transversal, Four Circumcircles, Circumcenters, Concyclic Points, Similarity.

Problem 547.
Triangle, Transversal, Four Circumcircles, Concurrency.

Problem 546.
Triangle, Angle Trisectors, 60 Degrees, Equilateral triangle.

Problem 545.
Acute Triangle, Squares, Altitudes, Area, Measure.

Problem 540.
Right Triangle, Square, Parallel, Perpendicular, Dissection, Area, Pythagoras.

Problem 539.
Right Triangle, Square, Parallel, Perpendicular, Dissection, Area, Pythagoras.

Problem 538.
Triangle, Perpendicular Bisector, Circumcircle, Midpoint.

Problem 535.
Sawayama - Thebault's theorem: Triangle, Incircle, Circle, Center, Tangent, Collinear.

Problem 534.
Right Triangle, Squares, Perpendicular, Dissection, Areas.

Problem 532.
Triangle, Circumcircle, Equal Angles, Perpendicular, Area.

Problem 531.
Triangle, Angle Bisector, Midpoint, Parallel, Perimeter, Semiperimeter.

Problem 528.
Triangle, Medians, Perpendicular, Measurement.

Problem 526.
Equilateral Triangle, Circumcircle, Chord, Measurement.

Problem 524.
Circle, Equilateral Triangles, Midpoint, Side, Measurement.

Problem 522.
Right Triangle, Circle, Diameter, Tangent.

Problem 521.
Triangle with three Squares, Altitude, Rectangle, Area.

Problem 520.
Triangle with six Squares, Ratio, Area.

Problem 519.
Triangle, Squares, Altitude, Perpendicular, Rectangle, Area.

Problem 517.
Right Triangle, Six Squares, Areas.

Problem 516.
Triangle, Cevian, Congruence, Angles.

Problem 515.
Triangle, Double Angle, Altitude, Measure.

Problem 514.
Triangle, Five Squares, Line, Area.

Problem 513.
Triangle, Double Angle, Exterior Angle Bisector, Measure.

Problem 512.
Triangle with three squares and concurrency.

Problem 511.
Triangle, Double Angle, Angle Bisector, Measure.

Problem 509.
Triangle, 120 Degrees, Angles, Congruence, Mind Map.

Problem 508.
Triangle with three Squares, Four triangle of equal Area.

Problem 507.
Triangle, Interior Point, 120 Degrees, Congruence, Angle.

Problem 505.
Right Triangle, Cevian, Sum of Segments, Angles.

Problem 504.
Equilateral Triangle, Angles, 45, 60 Degrees.

Problem 498.
Triangle, Angle Bisector, Double Angle, Measure.

Problem 497.
Triangle, Two Squares, Centers, Midpoint, 90 Degrees.

Problem 496.
Triangle, Two Squares, 90 Degrees, Concurrency, Angle Bisectors.

Problem 495.
Triangle, 120 Degrees, Angle Bisectors.