What is 1/4 of a turn

The circumference of a redwood tree trunk is 20π ft, and it is 100 ft tall. what is the approximate volume of the redwood tree trunk? 1,000π ft3 10,000π ft3 4,000π ft3 40,000π ft3

Is the point (0, 8) on the x-axis or y-axis? how do you know?

If t17 = 3 (t5) in an arithmetic progression, find t1 in terms of d.