Answer:
Circle
Step-by-step explanation:
The equation for a circle is in the form (x - h)² + (y - v)² = r², where (h, v) is the center of the circle and r is the radius.
A circle with its center at the origin will have an equation that looks like x² + y² = r², which is the form this equation is in.
That's how we know this equation belongs to a circle!
Hope this helps :)
