Explanation:
There are 2 ways you can do this:
A
Take your original $43 dollars and multiply it by 20% or .20
43*0.20 = 8.6 dollars
so your answer in turn would be $8.60
B
Take your dollar amount ($43) and move the decimal over to the left one spot ($4.30) and then double that to get 20% of your original amount (4.30*2 = $8.60)