Proposed Problem 391.
Triangle, Parallel lines, Collinear points.

Proposed Problem 392.
Triangle, Parallel lines, Concurrent lines.

Proposed Problem 393.
Triangle, Orthocenter, Circumcircles, Congruence, Collinear.

Proposed Problem 394.
Square, 90 Degree Arc, Diagonal, Congruence.

Proposed Problem 395.
Square, 15 Degree, Equilateral triangle.

Proposed Problem 396.
Square, Angle Trisectors, Congruence, Area.

Proposed Problem 397.
Triangle, Altitude, Midpoints, Congruence.

Proposed Problem 398.
Parallelogram, Area, Similarity, Congruence.

Proposed Problem 399.
Right triangle, Midpoints, Distance, Pythagorean theorem, Congruence.

Proposed Problem 400.
Triangle, Angle bisector, Circumcircle, Perpendicular, Congruence.