Volunteers were 3/4 finished with the walkathon when they reached the 4 1/2 kilometer mark. how many kilometers was the walkathon

Asocial networking site currently has 400,000 active members, and that figure is predicted to increase by 32% each year. the following expression represents the number of active members on the site after t years.

What percent of the circle below is shaded?

Can some one explain how to slove specifically, what is the value of x? 0.9(x+1.4)-2.3+0.1x=1.6 enter the answer as a decimal in the box. x= ?