To find the circumference of a circle, you do pi times the diameter. That would be 22pi.
To find the area of a circle, you do pi * r^2. The radius is the diameter divided by 2. That is 22 / 2, which is 11. Then, the area would be pi * 11^2 = pi * 121 = 121pi.
Lines form 180 degrees on either side. The negative sign simply implies direction (clockwise instead of counter-clockwise), which is negligible as 180 is exactly half of 360 so you'd form the same line.