Answer:
The answer is b. 74 and c. 80.
Step-by-step explanation:
The square root of a number is between 8 and 9 or:
[ 1 ] or
[ 2 ] (if we take 8 and 9 in the set of the solution).
Suppose we raise each member of [ 1 ] to the second power, that is:
We already know that .
And also that:
Then:
That is, <em>the number whose square root</em> is between 8 and 9, is thus between 64 and 81; so, the possible answers, <em>considering the options given,</em> are then 74 and 80, because these numbers are between 64 and 81 (<em>8.6 and 81.5 are not</em>). We can represent this <em>mathematically</em> as follows:
That is:
and
In other words, if we obtain the root squares of each number (74 and 80), all of them are between 8 and 9:
Or, approximately:
So, 74 and 80 are the numbers whose <em>root squares are between 8 and 9</em>.