Equation of a Circle

  1. 1
    Find the radius and the center of the circle that is defined by the equation: $$x^2+y^2=25$$ The general equation for a circle is $$x^2+y^2=r^2$$
  2. 2
    Find the radius and the center of the circle that is defined by the equation: $$x^2+y^2=81$$
  3. 3
    Find the radius and the center of the circle that is defined by the equation: $$x^2+y^2=40$$
  4. 4
    Find the radius and the center of the circle that is defined by the equation: $$(x-3)^2+(y+5)^2=36$$
  5. 5
    If the centre of a circle is (0,0) and the radius is 3 cm, find the equation of the circle.
  6. 6
    If the centre of a circle is (0,0) and the radius is 7 cm, find the equation of the circle.
  7. 7
    Determine the radius of the circle given the centre is at (0,0) and the point (3,4) is a point on the circumference.
  8. 8
    Determine the radius of the circle given the centre is at (0,0) and the point (-2,3) is a point on the circumference.

$$e=mc^2$$