Question

Please help me with this question

Answer 1

422 cm²

Explanation:

Surface area of the composite figure = (surface area of the upper cuboid + surface area of lower cuboid) - 2(base area of the lower cuboid)

Surface area of composite figure =
`(2(lw + lh + hw)) + (2(lw + lh + hw)) - 2(l*w)`

Upper cuboid has the following dimensions:

`l = 4, w = 3, h = 8`

Lower cuboid has the following dimensions:

`l = 10, w = 7, h = 5`

Plug these values into the formula

Surface area of composite figure

`= (2(4*3 + 4*8 + 8*3)) + (2(10*7 + 10*5 + 5*7)) - 2(4*3)`

`= (2(12 + 32 + 24)) + (2(70 + 50 + 35)) - 2(12)`

`= (136 + 310) - 24`

`= 446 - 24 = 422`

Surface area of composite figure = 422 cm²