The answer is a.
When you are solving problems like this you would use the equation y^2=4ax. The x and Y would be the coordinates. Based on the equation you have given the coordinates would be (6,12) and (6,-12), (24 is split up evenly between the y-axis).
Then we go on to solve the equation by plugging in the numbers 12^2=4a(6)
144=24a
144/24=24a/24
6=a
First we are going to find divided by 100 and multiply 20 is equal to four.
We are gonna use x to represent this number.
x/100 * 20 = 4
Solve for x
Therefore x = 20cm
Now that we found x the side of the larger square we are gonna find the area which is side^2.
20 * 20
Therefore the area of the larger square is 400cm^2
4848 inches is how long the bike will be