Answer:
6.47
Since it's just asking for the other side of the diameter, it's equivalent to the radius given already.
F = kq2 / r2
q = ne
F = k(ne)2 / r2
n = âš(r2F / ke2) = (r/e) âš(F/k)
k = 9 x 109 Nm2/C2
e = 1.6 x 10-19 C
n = [(4.2 x 10-10) / (1.6 x 10-19)] âš[(5.2 x 10-9) / (9 x 109)] ≅ 1.995 ≅ 2
The ingredients given are for 4 dozen cookies; however, Christian only want to make one dozen, meaning he requires only 1/4 the ingredients.
1/4 of 2 1/4 cups of while sugar is found the following way.
First, we write 2 1/4 as an improper fraction

1/4 of this is

Hence, Christian requires 9/16 cups of white sugar.
Similarly, the 1/4 of 3/4 cups of brown sugar is

Hence, Chrisitan requires 3/16 cups of brown sugar.
Therefore, the total cups of sugar required is the sum of

3/4 cups of sugar.