30. A man walks diagonally from one corner of a
rectangular lot to the opposite corner. If he
walks at the rate of 5 feet a second, and the lot is
50 feet by 120 feet, how many seconds will he
save by walking diagonally instead of walking
along the perimeter of the lot?
(A)8
(B) 10
(C) 17
(D) 34
How to find diagonal and side of a rectangle?