Explanation:
we have a rectangle, that is then cut in half diagonally into 2 right-angled triangles.
in our problem it does not matter which side is the larger and which is the shorter one, because the distance calculation for both cases involve one short and one long side. the sequence does not matter.
Mary walks one short and one large side to get to the opposite corner (from D to F) :
264 + 900 = 1,164 ft
Kate walks diagonally. and that diagonal is the Hypotenuse of the right-angled triangle with a short and a long side of the rectangle.
so, Pythagoras applies :
c² = a² + b²
with c being the Hypotenuse (the side opposite of the 90° angle), and a and b are the legs.
in our case that means
diagonal² = 264² + 900² = 69,696 + 810,000 =
= 879,696
diagonal = sqrt(879,696) = 937.9211054... ft ≈ 938 ft
so, Kate walked
1,164 - 938 = 226 ft
less than Mary.