Check the excellent book Treatise of plane geometry through the geometric algebra (276 pages) by Ramon González Calvet, University of Barcelona. Available for free download in Adobe Acrobat format (pdf). Covers not only plane Euclidean geometry and conics, but also spherical geometry and hyperbolical Lobachevsky's geometry.

Every geometrical theorem is proven by simple and unified algebraic methods, all proofs are presented in the utmost detail - no room is left for guessing. Solutions to all exercises are included as the last chapter. It is a jewel.

Regards, Vladimir