Question 1:
Look at the image.
First, we graph the points on a grid.
Then, we find the perpendicular bisectors and find where they intersect.
They intersect on the circumcenter of the triangle.
The circumcenter is (5,3)
Question 2:
The answer is III only because the perpendicular bisector for the longest side will always have to point outside the triangle in order to intersect with the other two perpendicular bisectors.
Question 3:
The answer is a perpendicular bisector because it is a perpendicular line that bisects a side of the triangles, which is the exact definition of a perpendicular bisector.
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