For this case we have that Cody average 165cm in height and that represented 10% higher than last year.
Then, making a rule of three we have:
165cm ----------> 100%
x --------------------> 10%
Where "x" represents the cm that equals 10%

To know the height of Cody last year, we subtract:

So, Cody had 148.5 cm on the first day of school last year.
Answer:
148.5cm