How do you find the median of these numbers $17.49, $11.29, $16.89, $11.79?

Good morning, kid. It's quite easy.

The median is the middle number in a set after you place them least to greatest:

$11.29, $11.79, $16.89, $17.49

Well, since the numbers in the set are even, meaning there are only 4 numbers, we pick out the 2 middle numbers which would be, $11.79 and $16.89. Find the average (add them and divide by 2) and you'll get the median.

$11.79 + $16.89 = $28.68/2 = $14.34

Thus, the median is: $14.34