Note: Consider x be the breadth of the box.
Given:
The surface area of the box is 204.25 square feet.
Length of the box = 10 ft
Breadth of the box = x ft
Height of the box = 6.5 ft
To find:
The value of x.
Solution:
The surface area of a cuboid is:

Where, l is length, b is breadth and h is height of the cuboid.
Putting
in the above formula, we get



Using distributive property, we get




Divide both sides by 33.


Therefore, the correct option is B.
First of all, you can simplify the 4 at the numerator and the 14 at the denominator (they're both multiple of 2):

Now, rationalize a denominator means that you have to get rid of the square root, in order to have an integer denominator.
To do so, remember that you can always multiply any number by 1 without changing its value, and you can always think of 1 as a fraction where numerator and denominator are equal:

Answer:
6.5
Step-by-step explanation: