The figure below shows a parallelogram ABCD with AE perpendicular to BC and AF perpendicular to CD. Prove that AC^{2} = CE.BC + CF.CD

Home | Search | Geometry | Problems | All Problems | Open Problems | Visual Index | 10 Problems | 831-840 | Triangles | Parallelogram | Perpendicular | Similarity | Email | Solution / comment | By Antonio Gutierrez