Help again please!!?

A conference centre contains five identical rooms. All of the rooms have square floors. Recently, the floors of the rooms have been painted, and a different pattern has been used for each room. Each room has a certain number of red circles painted on a white background in the patterns.


Room 1 has 9 red circles of equal area painted on a white background
Room 2 has 16 red circles of equal area painted on a white background;
Room 3 has 25 red circles of equal area painted on a white background;
Room 4 has 36 red circles of equal area painted on a white background;
Room 5 has 49 red circles of equal area painted on a white background;

Which room has the largest red-painted area on its floor? If one room has a greater red-painted area than the rest, give the number of that room (between 1 and 5 inclusive) as your answer. (If all of the rooms have the same red-painted area, give 0 as your answer).

Two things to remember

If a circle has radius R, then its circumference is 2 x pi x R;
If a circle has radius R, then its area is pi x R x R.

Assume the room is 1 square unit.

Room 1:
9 circles * (1/6)(1/6)(pi) = 0.7854 square units
(Note: 1/6 is the radius of each circle)

Room 2:
16 circles * (1/8)(1/8)(pi) = 0.7854 square units

Room 3:
25 circles * (1/10)(1/10)(pi) = 0.7854 square units

etc.

All of them have the same red-painted area, so 0.

Of course, this is assuming that the circles take up the entire room in a grid-like form.

Surely it depends upon the size of the circles that have been painted in each room...

Because these are all square numbers each room can be cut up into squares. i.e. room one will have 3 by 3 squares and room five 7 by seven squares.

Now if you have a circle in a square, say of side 10 the area of the square will be 100 and the area of the circle will be pi x 5^2 = 78.5
Therefore the area of the circle will be 78.5% the area of the square.
This implies that each room has 78.5% of them in red.
Therefore the answer is 0