Need assistance solving exponential equation: $64=0.8^d$x$100$

Question

Solve the exponential equation: $64=0.8^d \cdot100$ I tried doing: $64/100=80/100^d$ but since there is no common factor which gives these numbers with different powers I failed to find the value of variable $d$. How to solve it then?

Answer 1

$$64/100 = .64$$

So then you have $.8^d = .64$

What does $.8 \times .8$ equal?