I need help with this ASAP

An arc subtends a central angle measuring 7pi/4 radians what fraction of the circumference is this arc?

List x1, x2, x3, x4 where xi is the left endpoint of the four equal intervals used to estimate the area under the curve of f(x) between x = 4 and x = 6. a 4, 4.5, 5, 5.5 b 4.5, 5, 5.5, 6 c 4.25, 4.75, 5.25, 5.75 d 4, 4.2, 5.4, 6

Find the sum of the given arithmetic series. 24 + 17 + 10 + 3 + + (–39)