Answer:
1/16
Step-by-step explanation:
1/2 of 1/2 is 1/4 then 1/4 of 1/4 is 1/16
When Sam is 13 his mother will be 39 which is 3 times as old as he is. So Sam's mother will be 3 times as old as Sam will be in 11 years. (Your answer is 11 years.)
We have the equation:

By arranging this equation in terms of x and y, we have:

By using the method of completing the square, we have:

The center of this circle is:

So the equation that fulfills the statement is:

Finally, the right answer is c)
The answer is 72
the formula is (width+length)*2