Answer:
171 square ft
Step-by-step explanation:
Area of side walk of the pool = Are of outer square - Area of inner square
[tex] = {30}^{2} - {27}^{2} \\ = (30 + 27)(30 - 27) \\ = 57 \times 3 \\ = 171 \: {ft}^{2} [/tex]
