Step-by-step explanation: Consider a triangle with points A, B and C. You must create a perpendicular bisector of AB and then a perpendicular bisector of BC that crosses each other. Then you must label the center of that point D, and then using a compass tool, create a circle around the triangle.
the equation for a circle centered at orgin is x^2+y^2=r where r is the radius. multiplying, adding, or subtracting any numbers to the x and y components such as the other choices here causes the circle to be translated about the graph.