Solve the proportion for X.
5/2.5=
X/2
1
4
5.5
6.25

Step-by-step explanation:

5/2.5 = X/2

To solve a proportion, use the following equation:

(numerator * opposite denominator) =  (numerator * opposite denominator)

Substitute in given numbers

(5 * 2) = (X * 2.5)

Multiply to simplify

10 = 2.5X

Divide both sides of this equation by 2.5

Hope this helps :)

0.02

step-by-step explanation:

time of 9 192 631 770 periods of the radiation corresponding to the transition between the 2 hyperfine levels of the ground state of the caesium 133 atom at 0 k (but other seconds are sometimes used in astronomy)