Question 172472
Solution:

d = 1.4 sqrt (h)

now, we are required to find out the height at which the disatnce of 16 miles will be visible. To find the value of h we need to substitute the value of d as 16 in the above equation, hence

sqrt(h)= 16/1.4

squaring both the sides

h = (16*16)/(1.4*1.4)
  = 130.6