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:
C. The expression is not equivalent, but it is completely factored.
Answer:
y = 9.8995
Step-by-step explanation:
This question requires the use of basic trigonometry.
In this problem, we know one of the sides and two of the angles.
Since one of the angles is 45 degrees and the sum of all internal angles of a triangle is 180 degrees, the other angle can only be 45 degrees, making this an isosceles triangle - that is, the length of the other leg, x, is also 7.
You could use the soh cah toa mnemonic to figure it out, but here just using the a^2 + b^2 = c^2 should be sufficient since we know both legs of the triangle.
7^2 + 7^2 = 98, and the square root of 98 gives you about 9.8995, which sounds about right for this situation.
Hope this helped!
Answer:
87+87+81+86+89+83+89= 602. Divided by 7 because that’s how many numbers there were is 86 and that is your mean/average.