The mean is the average of all the lengths.

Add all the lengths of the jumping frogs together and divide that sum by the number of lengths.

The median is the middle number when the lengths are arranged numerically.

$7.6,7.6,9.2,12.5,13.9,14.1,15.6,17.5,20.3,21.7$

Since there are 2 middle numbers, average the two middle numbers.

The mode is the number that occurs the most often.

Find a number that occurs more than once.

$\frac{140}{10}=14$

$\frac{13.9+14.1}{2}=14$

The mode is: $7.6$