2218

Prove the red angles are congruent.

2181

The blue line bisects the legs of the right triangle. Prove the red points are concyclic.

1645

Medians of right triangles are parallel. Prove the red angle between the hypotenuses is double the green angle between legs.

931

Prove $a=c$ and $b=c+d$.

529

Find $x$.

421

Find $x$.

320

The gray lines are parallel to the sides of the right triangle. Prove $a+b=c$.

318

Prove the green line bisects the red line segment.

262

Prove the red line segments are congruent iff the blue line bisects the blue angle.

231

The circles are congruent. Prove the sides of the regular pentagon, regular hexagon, and regular decagon form a right triangle.

71

Prove $r=\dfrac{a+b-c}{2}$.

50

Prove the blue line segments are congruent.