Euclids 1.43 diagram
- A.J. Perea
[1.43] In any parallelogram the complements of the parallelograms about the diameter are equal to one another
BGKE (called BK by Euclid) and KFDH (called KD by Euclid) are the complements of parallelograms EH and FG about diameter AC. In what way are they equal? Move K to find the pattern.