Monday, September 22, 2008

Elearn Geometry Problem 180

Circles Tangent Externally

See complete Problem 180 at:

Circles Tangent Externally, Common External Tangents, Areas. Level: High School, SAT Prep, College geometry

Post your solutions or ideas in the comments.

1 comment:

  1. 1.
    for 2 fixed touching circle, CD is unique, so is EF
    reflect CD to C'D' by AB, C'D' touch the circle, C'=E and D'=F, and obvious that S_1=S_2

    mACD+mCDB=180°, AC//BD, [BCD]=[BAD], S=S_1+S_2 is obvious