[填空题]
Cylindrical logs of len3 /oqwpbm )8pg5q/+ut1,btl qf(hzingth 2.7 m and radius 7.5 cm are used to build a wooden7jyq; orcot +6 cabin. A wedge is cut from one log and the cross-section of this log is illustrated in the following d+ ;qo7 co6jrtyiagram.
1.Convert 108 degrees into radians, leaving your answer in exact values.
2.Find the length of the missing arc ABC. cm
3.Find the area of the missing sector ABCO. $cm^2$
4.Find the volume of this log. $cm^3$