That is a seriously tiny bathroom. Only a tiny baby would fit in it - standing, not lying down. My foot would not fit - without some toes being amputated.
But, since you asked the question, the answer is 0.388... recurring sq feet.
If a bathroom is 72 inches by 54 inches, it would take 27 1 foot square tiles to tile the bathroom. This can be found by converting from inches to feet, then calculating area by multiplying the length by the width.
0.006944... square feet.
736 square inches /144 = 5.111+ square feet, or 5 square feet 16 square inches
A square of 17.5 inches by 17.5 inches is 2.13 square feet.
1,008 square inches = 7 square feet.
1,600 square feet = 230,400 square inches.
100 square inches = 0.69444 square feet
200 square inches are 1.39 square feet.
10 square feet = 1,440 square inches.
106 square inches = ~0.74 square feet.
432 square inches = three square feet.
1,024 square inches = 7.11 square feet