Write the arithmetic series in summation notation 4+8+12+16

Asphere has a diameter of 10 in. what is the volume of the sphere?

What is the period of the sinusoidal function ?

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