Given parallelogram ABCD with its diagonals drawn. A line through B intersects AC at E, DC at G, and line AD at F. Observe that △AEF is similar to △CEB, and show that EB is the geometric mean of EG and EF.

The Ohio State University: College of Education and Human Ecology

Given parallelogram ABCD with its diagonals drawn. A line through B intersects AC at E, DC at G, and line AD at F. Observe that △AEF is similar to △CEB, and show that EB is the geometric mean of EG and EF.