The length of the rectangle is 30 m
The width of the rectangle is 20 m
The sidewalk is 3m wide on all sides, so
length of sidewalk = 30+6 =36 m
Width of sidewalk = 20+6 = 26 m
Area of rectangle =
Area of rectangle =
Area of rectangle including sidewalk =
Hence, area of sidewalk alone = area of rectangle with sidewalk - area of rectangle
Surface Area = m²