Simple,
using the Pythagorean Theorem...

You have the hypotenuse (C) and one of the legs (A)
So, plug in what you know...

144+

=400
Now,isolate


-144 -144
Leaving you with...

So, now,

, to find what b is..
b=16
Thus, your answer.
Answer:
Steps For Solving Real World Problems
2. Highlight the important information in the problem that will help write two equations.
3. Define your variables.
4. Write two equations.
5. Use one of the methods for solving systems of equations to solve.
6. Check your answers by substituting your ordered pair into the original equations.
System of equations subtraction method
In the addition/subtraction method, the two equations in the system are added or subtracted to create a new equation with only one variable. ... Substitute the variable back into one of the equations and solve for the other variable. Check the solution--it should satisfy both equations.
The largest number that 8c could be is -15
Cut the 4 corners off and you will have an 8-sided octagon