Geometry plz help

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A rectangular solid has a top face with surface area of 28 ft, a front face with surface area of 20 ft, and a side face with surface area of 70 ft. What is the volume of this solid?

  • Geometry plz help -

    There are two ways to approach the problem:
    1. Calculate the side lengths, a,b and c.
    ab=28....(1)
    ac=20....(2)
    bc=70....(3)

    Therefore by dividing ac by bc, we get
    a/b=2/7
    substitute a=2b/7 into equation (1) gives 2b/7*b=28 => b²=98 => 7√2

    You can calculate similarly the other sides.

    2.
    You are looking for the product abc, from which ab=28
    So
    abc=ab*bc*√((a/b)/ab)
    All the products are known, the quotient has been calculated in part 1.
    So the volume abc can be calculated directly.

  • Geometry plz help -

    umm still lost.....

  • Geometry plz help -

    Did you try method 1 or method 2?

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