Answer:
By definition of congruence
Step-by-step explanation:
Triangle ABC is congruent to triangle DBE
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:
Use Bidmas, solve all the inner brackets (), with first division, then multiplication then addition then subtraction
Answer:
4/7 as a decimal is 0.57142857142857.
She used the associative property which should only be used with positive numbers (sorry if it isn't the answer you're looking for)