Triangles: Theorems and Problems 4

Geometry Problem 1415.
Right Triangle, Altitude, Incircle, Excircle, Tangency Points, Isosceles Triangle.

Geometry Problem 1414.
Right Triangle, Altitude, Incircle, Excircle, Tangency Points, Isosceles Triangle.

Geometry Problem 1413.
Right Triangle, Incircle, Excircle, Tangency Points, Isosceles Right Triangle.

Geometry Problem 1412.
Right Triangle, Incircle, Excircle, Tangency Points, 45 Degree Angle.

Geometry Problem 1411.
Right Triangle, Incircle, Excircle, Tangency Points, Isosceles Right Triangle.

Geometry Problem 1410.
Right Triangle, Incircle, Excircle, Tangency Points, 45 Degree Angle.

Geometry Problem 1409.
Right Triangle, Incircle, Excircle, Collinear Tangency Points, Collinearity.

Geometry Problem 1408.
Right Triangle, Incircle, Excircle, Incenter, Midpoint, Tangency Point, Collinearity.

Geometry Problem 1407.
Right Triangle, Incircle, Excircle, Collinear Tangency Points, Collinearity.

Geometry Problem 1402.
Triangle, Three Tangent Circles, Parallel Diameter, Collinear Points.

Geometry Problem 1401.
Right Triangle with three circles on the sides, Isosceles, Diameter, Center, Tangent, Congruence.

Geometry Problem 1400.
Triangle with three rectangles on the sides, Perpendicular Bisectors, Concurrency.

Geometry Problem 1399.
Triangle, Circumcircle, Perpendiculars, Angles, Congruence, Cyclic Quadrilateral.

Geometry Problem 1396.
Triangle with three rectangles on the sides, Vertices, Perpendicular lines, Concurrency.

Geometry Problem 1395.
Triangle with three rectangles on the sides, Midpoints, Perpendicular lines, Concurrency.

Geometry Problem 1391.
Two Triangles, Ratio of Areas, Circumcircle.

Geometry Problem 1390.
Triangle, any point, perpendicular, sum of the squares.

Geometry Problem 1389.
Triangle, 40-120-20 degree, Angle, Congruence.

Geometry Problem 1388.
Triangle 40-60-80 degree, Incenter, Congruence.

Geometry Problem 1387.
Quadrilateral, Double Angle, Congruence, Isosceles Triangle.

Geometry Problem 1386.
Thabit ibn Qurra (826 -901) Theorem and more conclusions, generalized Pythagorean Theorem to any triangle.

Geometry Problem 1385.
Triangle, Orthocenter, Circle, Circumcircle, Angle Bisector, Midpoint, Collinear Points.

Geometry Problem 1384.
Triangle, Orthocenter, Circle, Circumcircle, Angle Bisector, 90 Degree.

Geometry Problem 1383.
Triangle, Median, Circle, Chord, Secant, Sum, Product.

Geometry Problem 1381.
Parallelogram, Exterior Point, Triangle, Area.

Geometry Problem 1378.
Parallelogram, Diagonal perpendicular to a side, Distances from a Point to Vertices, Measurement.

Geometry Problem 1377.
Isosceles Triangle, Interior Cevian, Equal Sum of Exradii, Excircle.

Geometry Problem 1376.
Isosceles Triangle, Interior Cevian, Excircles, Tangency Points, Parallel Lines.

Geometry Problem 1375.
Isosceles Triangle, Interior Cevian, Exradius, Excircle, Altitude to the Base.

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 1363.
Square, Angle Bisector, Perpendicular, 45 Degrees, Angle, Sketch, iPad Apps.

Geometry Problem 1362.
Equilateral Triangle Inscribed in a Circle, Lunula, Ratio of Areas, Tangent, Sketch, iPad Apps.

Geometry Problem 1361.
Triangle, Two Nine-Point Circles, Feuerbach's Circle, Euler's Circle, Congruent Angles, Sketch, iPad Apps.

Geometry Problem 1360.
Triangle, Nine-Point Circle, Feuerbach's Circle, Euler's Circle, Cyclic Quadrilateral, Concyclic Points, Sketch, iPad Apps.

Geometry Problem 1359.
Triangle, Circumcircle, Congruent Angles, Midpoints.

Geometry Problem 1356.
Quadrilateral, Triangle, Angle, 30 Degrees, Congruence.

Geometry Problem 1355.
Triangle, Midpoint, Median, Circle, Chord, Equal Product of measure of segments.

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

Geometry Problem 1349.
Three Squares, 90 Degrees, Perpendicular Lines, Diagonal. Math Infographic.