Two vertices of a right triangle have coordinates )5, 1) and (2, -1) . the line segment created by connecting these points is the hypotenuse of the right triangle which could be the coordinate and third vertex? Please help!!
(2, 1)
(2, 5)
(2, -5)
(1, -1)

This is something you'll need a T table for, or a calculator that can compute critical T values. Either way, we have n = 10 as our sample size, so df = n-1 = 10-1 = 9 is the degrees of freedom.

If you use a table, look at the row that starts with df = 9. Then look at the column that is labeled "95% confidence"

I show an example below of what I mean.

In that diagram, the row and column mentioned intersect at 2.262 (which is approximate). This value then rounds to 2.26