To find:The approximated threshold(in dollars)in 2012,using the given model.

Concept: Modeling is a method of simulating the real life situations with mathematical equations. Using these models we can forecast the future behavior. We can translate the mathematical word problem into a math expression using variables.
Calculation:
The given model is Number of students $=y=2.719x^2+196.1x+8718$
Using this model, we can approximate the threshold for a single person between the years 1999 and 2013.
y is the approximated threshold in dollars.
Here, x= 0 corresponds 1999
x=1 corresponds 2000.
x=2 corresponds 2001.
x=3 corresponds 2002.
x= 4 corresponds 2003.
x= 5 corresponds 2004.
So, x= 13 corresponds 2012.
So, substituting x= 6 in the given model, we get the approximated threshold (in dollars) in 2005.
So, estimated threshold in $2005=2.719{\left(6\right)}^2+196.1\left(6\right)+8718$
= 2.719(36) + 196.1(6) + 8718
= 97.884 + 1176.6 + 8718
= 9992.484 dollars
Final statement:
Therefore, the approximated threshold (in dollars) in 2005 is 9992.484 dollars.