SURVEY + SQUARE

正負

一本暑期作業,Called

Pilot's Summer......  

注 : P.6 - S.1

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謝解答.

mk311111

                               
登錄/註冊後可看大圖

圖就先放上來

1.
In ΔABC,
AB²+BC²=AC² (Pyth. thm.)
AC=√ 6²+8²   km
AC=10 km

2. In ΔABC,
sin∠ACB=AB/AC
∴  ∠ACB=53.13° (cor to 2 d.p.)
∴the bearing is N53.13°W

3. The Reservoir should be  at point E.
BE
=CE
=AC/2
=5 km

4.In ΔBEF,
cos∠EBF=BF/BE
cos∠EBF=4/5
∴  ∠EBF=36.87° (cor to 2 d.p.)

∠CBE=90° -∠EBF
=53.13°
∴the bearing is S53.13°W

很大機會錯的

[ 本帖最後由 mk311111 於 31/8/2008 01:01 PM 編輯 ]