need help with grade 12 data management

Hi. I have two questions"

1) Given the following coefficients of correlation, state what percent of variation in y is due to the variation in x.

A) r=0.41 b)r=-0.93 c)r=-1.0

How would I do a question like this?

and...

2) given the chart:

http://img66.imageshack.us/img66/3757/chartft8.png

find the equation of the line of best fit. How did you do this?

*I have no clue how to find the equation. I am so confused.

Thanks in advance for any help, I greatly appreciate it.

Jenn