Susan has the wrong center and the wrong radius.
The center should be (3,-4) and the radius is 6.
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Reason:
Compare
to the template

We have
Susan mixed up the positive and negative signs for h and k.
It might help for her to rewrite
into
to better spot h and k.
To find r, this is what the steps would look like

Susan might have mistakenly thought the 36 was the diameter, and further reasoned that radius = diameter/2.
That formula is indeed true. However, the 36 is not the diameter.