A [Power Law](https://en.wikipedia.org/wiki/Power_law) distribution occurs whenever "a relative change in one quantity results in a proportional relative change in the other quantity." For example, if *y* = 120 when *x* = 1 and *y* = 60 when *x* = 2 (i.e. *y* halves whenever *x* doubles) then when *x* = 4, *y* = 30 and when *x* = 8, *y* = 15.
Therefore, if I give you any pair of co-ordinates (x1,y1) and (x2,y2) in a power law distribution, you can plot the entire rest of the distribution and tell me the value of *y* for any other value of *x*. 
Given a pair of co-ordinates (x1,y1) and (x2,y2) and another x co-ordinate *x3*, return the value of *y3*
```
powerLaw(x1y1, x2y2, x3)
e.g. powerLaw([1,120], [2,60], 4)
- when x = 1, y = 120
- when x = 2, y = 60
- therefore whenever x doubles, y halves
- therefore when x = 4, y = 60 * 0.5
- therfore solution = 30
```
(x1,y1) and (x2,y2) will be given as arrays. Answer should be to the nearest integer, but random tests will give you leeway of 1% of the reference solution to account for possible discrepancies from different methods.
import math
def power_law(x1y1, x2y2, x3):
  x1=x1y1[0]
  y1=x1y1[1]
  x2=x2y2[0]
  y2=x2y2[1]
  x=x2/x1
  y=y2/y1
  if x1==x2: return y2
  return round(y1*y**(math.log(x3/x1)/math.log(x)))
import math
def power_law(x1y1, x2y2, x3):
  x1=x1y1[0]
  y1=x1y1[1]
  x2=x2y2[0]
  y2=x2y2[1]
  x=x2/x1
  y=y2/y1
  if x1==x2: return y2
  return round(y1*y**(math.log(x3/x1)/math.log(x)))