Final answer:
To find the total area of all six faces of the tunnel, you need to find the area of each face and then add them together. The area of a rectangular face can be found by multiplying the length and width.
Step-by-step explanation:
To find the total area of all six faces of the tunnel, we need to find the area of each face and then add them together. Since the tunnel is a rectangular prism, it has three pairs of congruent faces. The area of a rectangular face can be found by multiplying the length and width. In this case, we need the cross-sectional area of the wider part of the tunnel, which is given as 7.85×10-5 m². Since there are two wider faces and four narrower faces, we multiply this area by 2 for the wider faces and by 4 for the narrower faces. Therefore, the total area of all six faces of the tunnel is 2(7.85×10-5) + 4(7.85×10-5) = 4(7.85×10-5) = 3.14×10-4 m². In terms of π, this can be written as 3.14π×10-4.