Answer:
It is an exponential growth.
If we keep adding the most recent 2 numbers (the Fibonacci sequence)
1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89
we will see that the last number divided by the previous number (for example 89 / 55 = 1.6181818182 approaches a limit of 1.6180339 which is known as the phi ratio.
Basically, we are looking for a number with a rate of growth equal to itself.
Phi is an irrational number equal to [1 + sq root (5) / 2]
which equals 1.6180339...
Then we can say that the NEXT Fibonacci number equals the
PREVIOUS Fibonacci number times "phi".
Next number = previous number * phi
Explanation: