Since we are trying to find x(the missing number), we need to get x by itself. x is being multiplied by 28. To undo this, divide both sides by 28. This will cancel out 28 and leave x by itself.
square foot of 49 is the correct one because 6.27316543222718… keeps going and does not stop the other 2 is irrational and square root of 49 is 7 basically meaning is rational