So for this, you'll be using the pythagorean theorem, which is
. In this case, 10 and 24 are the legs, and AB is the hypotenuse. Our equation will be 
Firstly, solve the exponents: 
Next, combine 100 and 576: 
And lastly, square root both sides to get 
And in short, Line AB is 26 ft, or the first option.