Answer:
c-- 3.84 m approx.
Explanation:
You want the diagonal length of a cuboid with a 1.5 m square base and a height of 3.2 m.
Estimate
Your geometry sense tells you the length from one corner to the opposite corner must be longer than the longest edge, and shorter than the sum of the edges you follow to get from one corner to the other.
For diagonal d, this means ...
3.2 < d < 3.2+1.5+1.5
3.2 < d < 6.2
Only one answer choice is in this range: approx. 3.84 m.
Computation
If you want or need to compute the actual length, it can be found using the Pythagorean theorem. It is the root of the sum of the squares of the edge lengths:
d = √(3.2² +1.5² +1.5²) = √(10.24 +2.25 +2.25) = √14.74
d ≈ 3.83927 ≈ 3.84 . . . . meters
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Additional comment
In general, a parallelepiped will have opposite faces that are parallelograms. Here, we are given that two of the opposite faces (the bases) are squares. In order for a space diagonal to be 3.84 m with a height of 3.2 m, the figure must be a cuboid, with all angles right angles.
A general parallelepiped will have 4 different length diagonals. The fact that there is only one diagonal length constrains the geometry.