To find the height of the tree, we can set up a proportion based on the similar triangles formed by the heights of the objects and their corresponding shadow lengths.
Let \( h \) be the height of the tree in inches. According to the problem, we can set up the proportion as follows:
\[ \frac{\text{Height of the tree}}{\text{Length of the tree's shadow}} = \frac{\text{Height of the student}}{\text{Length of the student's shadow}} \]
Substituting the known values into the equation, we have:
\[ \frac{h}{60} = \frac{68}{17} \]
Now we can simplify the right side:
\[ \frac{68}{17} = 4 \]
Now we can rewrite the proportion:
\[ \frac{h}{60} = 4 \]
To find \( h \), we can multiply both sides by 60:
\[ h = 4 \times 60 \]
Calculating this gives:
\[ h = 240 \]
So, the height of the tree is 240 inches. To convert this height into feet, since there are 12 inches in a foot, we divide by 12:
\[ \frac{240}{12} = 20 \]
Thus, the height of the tree in feet is
\[ \boxed{20} \]