Squares in a Rectangle For any rectangle, the sum of the squares of the distances from any point P to two opposite corners is equal to the sum of the squares of the distances from that point to the two other corners (so, above, a² + c² = b² + d²). This remains true whether the point is inside or outside the rectangle, on a side or a corner, or even outside the plane. credit: Greg Ross http://www.futilitycloset.com/2013/04/07/balance-5/