Final answer:
The central angle for boys in the cooking club's pie chart decreased by 22.97 degrees from 2018 to 2019, going from 310.5 degrees to 287.53 degrees due to a change in the number of members.
Step-by-step explanation:
To calculate the central angles in the pie chart for the boys in the cooking club for the years 2018 and 2019, we need to find the proportion of the boys out of the total number of club members each year and then multiply by 360 to get the angle.
In 2018, the number of boys was 69, and the number of girls was 11, giving a total of 80 members. To find the central angle for the boys in 2018, we do the following calculation:
(Number of boys / Total members) x 360 = Central angle for boys
(69 / 80) x 360 = 310.5 degrees
In 2019, there was one fewer boy and six more girls, meaning there were 68 boys and 17 girls, with a total of 85 members. The calculation for the central angle for boys in 2019 is:
(68 / 85) x 360 = 287.53 degrees
The difference in the central angle from 2018 to 2019 for the boys is:
310.5 degrees - 287.53 degrees = 22.97 degrees
Therefore, the central angle for the boys' section in the pie chart decreased by 22.97 degrees from 2018 to 2019.