Question

Give the equation of the circle centered at the origin and passing through the point (4,0)

Answer 1

Answer:

x² + y² = 4²

Step-by-step explanation:

The standard equation of a circle centered at the origin and with radius r is

x² + y² = r²

Note that the point (4, 0) is 4 units horizontally and to the right of the center (0, 0).  Thus, we know immediately that the radius is 4.

Thus the equation of this circle is x² + y² = 4²