The underlined number is in the hundredths place, so that means that we're going to round there. That means that you look at the number to its right and if it's lower than 5, it stays the same. However, if it's 5 or higher, you round it up. For example, if the number was 8.386, we would round it to 8.39.
(2,-5) move up three steps is (2, -2). if you draw it on a paper(and draw lines to connect them), you can see that they form a right triangle. apply a²+b²=c² and you should get 3²+2²=(√13)²