Marty created a design idea for observing how a shadow changes throughout the year. For his design, he needed an object that did not move, so he used the school's flagpole. He measured the flagpole's shadow on the first day of each month at exactly 9:00 a. m. Marty's data is shown in the table.
Month
Length of Shadow
(in feet)
August
23
September 24
October
25
November
26
December
27
What is the pattern in the data Marty collected?