A and b are irrational because we can’t graph them on a number line. One is a square root and the either is a decimal which is combined with the square root. The second is rational because the square root of 225 is 15 which can be graphed on a number line. 2.5 can also be graphed on a number line. We multiply these and get 37.5 which is possible to graph. 20 is irrational since it is not a perfect square. Therefore, it is difficult to add a square root and a decimal.
