Monday, September 15, 2008

Elearn Geometry Problem 179

Rhombus, Square, Diagonal, Angle

See complete Problem 179 at:

Rhombus, Square, Diagonal, Angle. Level: High School, SAT Prep, College geometry

Post your solutions or ideas in the comments.


  1. DA=DC=DE, D is the circumcenter of CAE, mAEC=90°/2=45°

  2. notice that AD = CD = DE so if we draw a circle with centre D and radius DE, say, then it will pass through A, C and E. but angle ADC is 90 degrees and it is also the central angle. so angle AEC will be half of angle ADC that is angle AEC = 45 degrees.