Find the value of a, b and c and explanation

Data was collected on myrtle beach for 11 consecutive days. each day the temperature and number of visitors was noted. the scatter plot below represents this data. how many people visited the beach when the temperature was 84 degrees?

Aline passes through 3,7 and 6,9 what equation represents the line

The midpoints of the sides of the large square are joined to form a smaller square. what is the area of the smaller square