The number of wolves in a wildlife preserve is estimated to have increased continually by 3% per year. if the population is now estimated at 5,400 wolves, how many were present 10 years ago?

For the answer to the question above, Well, first let us put up a functional equation. 
Since this is an exponential function, it'll be: f(t)=54,000*1.03^t 
But we want to know how many wolves there were 10 years ago. 
For that, we simply "turn time around", as in: f(t)=54,00*1.03^-t 
This displays a decreasing number of wolves, as you turn back time. 

Now we simply calculate 54,000*1.03^-10 
which is approximately 40,200?

the total of angle's in traingle is 180

so 85+53+c=180

c=180-138

c=42