a) h = 2sqrt2 because for a 45-45-90 triangle both legs have the same measurement and to find the hypotenuse, you would multiply the leg by square root of 2.
b) d = sqrt3 because in order to find the short leg for a 30-60-90 triangle, you would need to divide your long leg by a square root of 3 (if you have the hypotenuse and wanted to find the short leg, divide the hypotenuse by 2).