Answer:
r = 9
Step-by-step explanation:
cross multiply
9 * r = 81
9r = 81
divide both sides by 9
r= 81/9
r = 9
The answer is C(-2, 6).
I think you forgot the y in the first equation (with the -4.
Answer:

Step-by-step explanation:
To solve this problem, we can use the area of a circle formula as shown below:

<em>A = area</em>
<em>r = radius</em>
<em />
First we need to find the radius.
The radius is half of the diameter. For this problem, the radius is going to be 3.
Now, plug the values into the equation:


The window's area is 
It can be either 1.4 or 1.3 or your looking to your nearest 5th