False, since if there are two perpendicular lines with gradients m1 and m2, then m1*m2 = -1.
Taking this example -5/2 multiplied by 5/2 is equal to -25/4, which is not equal to -1.
To find the actual gradient of the perpendicular line you would have to divide -1 by -5/2, which gives you 2/5.
