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
He will have 7.75 left from the 20 dollar bill he spent
Answer:
25π
Step-by-step explanation:
If you add the 3/4s with the 2 1/4 hour breaks it would be 1 hour and 1 fourth.
Then you take 10-1/2 hours and subtract it by 1 hour and 1 fourth.
So you would get 9-1/4 hours