We can find out the average amount of rainfall per hour by using the formula:

So we are given that 3.6 cm of rain fell in 4 and 1/2 hours.
4 and half hours is 4.5 hours in decimal.
So plugging these in the formula above to find average rainfall,

So dividing 3.6 by 4.5 we get ,
Average amount of rainfall is 0.8 cm / hour.
Answer: The average rainfall is 0.8 cm per hour.