Answer:
123 m²
Explanation:
Surface area of the object = surface area of the bigger rectangular prism + (surface area of the smaller rectangular prism - area of the smaller rectangular prism base)
Surface area of the bigger rectangular prism:
L = 7 m
W = 3 m
H = 3 m
S.A = 2(LW + WH + LH)
S.A = 2(7*3 + 3*3 + 7*3)
S.A = 102 m²
Surface area of the smaller rectangular prism:
L = 3 m
W = 3 m
H = 1 m
S.A = 2(LW + WH + LH)
S.A = 2(3*3 + 3*1 + 3*1)
S.A = 30 m²
Area of the base of the smaller rectangular prism = L*W
L = 3 m
W = 3 m
Area = 3*3 = 9 m²
Surface area of the object = 102 + (30 - 9)
= 102 + 21
= 123 m²