Okay, first, given the equation, we need to find out what the radius of the circle is. Let us state the general equation of a circle:

Where

is the centre of the circle. In this case, we don't need to know the centre. Just the radius.
Let us start by converting the equation into standard for, which I typed above. Divide both sides by 81.

Great! We now know the radius of the circle. It is

because it is the bottom fraction. Now we know that the radius is 9.
So now lets input this into the area of circle formula:
Now we insert our radius.
You can convert that into a decimal if you wish.
Hope this helped!
~Cam943, Moderator
39 times 3 and 15 times 3 then 27 times 2 then add together to get 216
Answer:
c. f(x) = (x + 4)(x - 1)
Step-by-step explanation:
Since you're familiar with the product of two binomials:
(x +a)(x +b) = x² + (a+b)x + ab
you know that the constants in the binomial factors must ...
- have a product of -4
- have a sum of +3
__
All of the choices except B have binomial constants that have a product of -4.
In order, the sums of the remaining choices are ...
A: 1-4 = -3
C: 4-1 = 3 . . . . this is the correct choice
D: -2+2 = 0