Al and Curt live at opposite corners of a square lot; Beth and Dawn live at the other two corners. They all carry water from a spring located within the lot. The spring is feet from Al, feet from Beth, and feet from Curt. How far is the spring from Dawn?
Subtract Eq. (2) from Eq. (1)
Subtract Eq. (3) from Eq. (4)
Compare Eq. (5) and Eq. (6)