Question

80 km is 9% of what distance??

Answer 1

set up a proportion , 
80/x    9/100
9 is over 100 because it is a percent and 100% is the highest  %.
 doing a proportion   you cross multiply getting you..
9x =80 x 100 
9x= 800
divide by 9 on both sides
that determines your answer 
you try !