Cody was
\[165\,\text{cm}\] tall on the first day of school this year, which was
\[10\%\] taller than he was on the first day of school last year.
How tall was Cody on the first day of school last year?
If Cody was 165 cm tall on the first day of school this year, and this height represents a 10% increase compared to his height on the first day of school last year, let's calculate his height for last year.
Let x be Cody's height on the first day of school last year. The 10% increase in his height would be represented as x + 0.10x (which is the same as 1.10x). This total needs to equal his current height of 165 cm.
So the equation we need to solve is:
1.10x = 165
To find x, we would divide both sides by 1.10:
x = 165 / 1.10
x = 150
Therefore, Cody was 150 cm tall on the first day of school last year.