Geometry Problem 971.
Equilateral Triangle, Rectangle, Common Vertex, Sum of Right Triangles Areas.

Geometry Problem 972.
Equilateral Triangle, Vertices, Three Parallel, Equal Circles, Perpendicular Bisector.

Geometry Problem 973.
Three Parallel, Square, Vertices, Distance Between Two Parallel Lines, Side, Metric Relations.

Geometry Problem 974.
'Begonia Theorem', Cevian Triangle, Reflection of a point in a line, Concurrency of Lines. GeoGebra, HTML5 Animation for Tablets.

Geometry Problem 975.
Isosceles Right Triangle, 45 Degrees, Angle Bisector, Hypotenuse.

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

Geometry Problem 977.
Acute Triangle, Circumcenter, Orthocenter, Distance, Circumradius, Altitude, Metric Relations.

Geometry Problem 978.
Parallelogram, Diagonal, Transversal, Similarity, Metric Relations.

Geometry Problem 979.
Triangle, Cevian, Angle Bisector, Concurrency, 90 Degrees, Perpendicular.

Geometry Problem 980.
Equilateral Triangle, Vertices, Three Parallel, Equal Circles, Construction.