This is a question based on the application of Pythagoras. In the question a diagram of the triangle ABC will be provided and we would be able to see that we would need to work out the hypotenuse. Thus using Pythagoras:(AC)2 = (BC)2 + (AB)2AC = [(BC)2 + (AB)2]1/2
Thus by simple substitution we can obtain that the length is 13Normally we would put +- but as it is a length it has to be +