读图,甲、乙两地的相对高度是( )
A:800米
B:1 300米
C:300米
D:600米
There must have been some ____ (understand). I didn't order all these books.
(Ⅰ)求 sinB 的值;
(Ⅱ)若 b=42 ,且 a=c ,求△ABC的面积。