To find the values of 'a' and 'b', we need to use the formula for finding the area of a parallelogram:

Area of parallelogram = base x height

In this case, we are given that the base (a) is 4 cm and the height (b) is unknown, and the area is 45 m^2.

We need to convert all measurements to the same units, so let's convert 4 cm to meters:

4 cm = 0.04 meters

Now we can plug the values into the formula and solve for 'b':

45 m^2 = 0.04 m x b
b = 45 m^2 / 0.04 m
b ≈ 1125

So, the height 'b' is approximately 1125 meters.