【进阶级练习题68】: @- x( A5 v! ]8 [) Y) e
+ s, F' g- H) ]( P9 Q' ~: d
求:" a L3 S( h5 R
1. ∠a 之角度值为何?* s8 k4 n. {( _3 g! J
a. 57.296° b. 57.692° c. 57.926°6 w* x% @& t3 Z0 ], D |/ p# v
2. 剖面线区域之面积为何? * L, |5 V* N$ i ?* T, l, _ a. 1562.5000 b. 1562.5010 c. 1562.51001 W8 b3 @5 l5 F$ l- E) t
3. 剖面线区域型心之y座标为何? ) W/ v/ c/ \* x" U a. 60.7227 b. 60.7272 c. 60.7722