there is no mistake about it,
it was a ghost!! Maybe you spilled something on the floor that has turned out to be luminous. Try covering the area with something lightproof for a couple of days, then remove the cover after turning the light off and see if it still glows. If it does, you may indeed have a ghost (but probably not).
No. It would be impossible to see the moon every night from her bedroom window. That's because the Moon moves every night.
An Apollonian circle is a diagram of two families of circles such that every circle in the first family intersects every circle in the second family orthogonally.
its five days
Every diameter of the circle.
a circle within a circle within a circle decrealsing in size every time
... center of the circle.
If one is, they all are!
It is the center of the circle
Every meridian of longitude on Earth crosses the Antarctic Circle, the Arctic Circle, and every other parallel of latitude on Earth.
Yes; the circle is a special case of an ellipse.
No, because the value of pi remains the same for any circle.
A circle has a round shape in which every point on the circle is the same distance from one point called "the center". The center of a circle is not on the circle.