[填空题]
Cylindrical logs of lengkga 5 tb1(8 jfc7ndo +tbat04fvaass04+ 51ft hl ;ahqth 2.7 m and radius 7.5cm are used to build a wooden cabin. A wedge is s ath;5+vfa0l4s1 qah cut from one log and the cross-section of this log is illustrated in the following diagram.
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. $cm^3$