The correct answer is:
B. 
The radius of sphere A is multiplied by to produce the radius of sphere B.
<span>To minimize the perimeter you should always have a square.
sqrt(289) = 17
The dimensions should be 17 X 17
To see , try starting at length 1, and gradually increase the length.
The height decreases at a faster rate than the length increases, up until you reach a square.
Or if you want to use algebra, Say the width is 17-x
Then the length is 289/(17-x)
Now, this is bigger than 17+x, as shown here:
289/(17-x) > 17+x
289 > 289 - x^2
which is true.
so the perimeter would be bigger than 2 * (17- x + 17 + x) = 2 * (2 * 17) = 4 * 17
Again, the dimensions should be a square. 17 X 17.</span>
Answer: False, there are actually 900 different three-digit numbers
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Explanation:
The three digit numbers span from 100 to 999, including both endpoints.
This means we have 999-100+1 = 900 different three-digit numbers.
You subtract the endpoints (large-small) and add 1 to include the lower endpoint.
Here's a smaller example of why this works: say you had the set {1,2,3,4} and we wanted to count the number of items in this set. Clearly there are 4 items. Note how subtracting the endpoints 4-1 gets us 3 instead, so we add on 1 to include that left endpoint.
