I'm not understanding how to dothese 2 problems:

For each correlation coefficient below, calculate what proportion of variance is shared by the two correlated variables:

r = 0.25

r = 0.33

r = 0.90

r = 0.14

2. For each coefficient of determination below, calculate the value of the correlation coefficient:

r² = 0.54

r² = 0.13

r² = 0.29

r² = 0.07