-12c to the fourth power +18c to the third power! :)
It would take 630 seconds to boil the water.
Answer:
The measurement of the central angle AOB is 45 degrees
Step-by-step explanation:
To solve this problem, we will have to work with fractions.
We will get the fraction of area the shaded portion is when compared to the whole garden.
First of all, we will need to calculate the area of the garden which is 
in this case, our radius is 8 inches.
Next, we will compare the area of the sector to the area of the garden. This will be
This will be the shaded area/ area of the whole garden
= 

We will now convert this ratio to an angle by multiplying it by 360 degrees.
This will be:

The measurement of the central angle AOB is 45 degrees