The area of a triangle, with a base length of 10 feet. Write a formula for the given measure, and tell what each variable represents. Then identify which variable depends on which formula. Sorry if im asking to much.

The line plot below represents the number of letters written to overseas pen pals by the students at the waverly middle school.each x represents 10 students. how many students wrote more than 6 and fewer than 20 letters. a.250 b.240 c.230 d.220