We know that:

is an equation of a circle.
When we substitute x and y (from the pairs we have), we'll get a system of equations:

and all we have to do is solve it for a, b and r.
There will be:

From equations (II) and (III) we have:

and from (I) and (II):

Now we can easly calculate a and b:

Finally we calculate

:

And the equation of the circle is:
Answer:
greater than cb and less than ab ig
Answer:
score = 63
Step-by-step explanation:
1. To write the proportion take the score of the test over the number of points and set it equal to the percent over 100
score 90
----------- = -----------
70 100
Using cross products
100 * score = 90*70
100 score = 6300
Divide by 100
100/100 * score = 6300/100
score = 63
Answer: the answer is d
Step-by-step explanation: