Q and R are 9 km apart and are both due east of O. The bearing of P and O is SBE, where 0<B<90.If PO =15km, PQ=6km and PR=8km.FINd B,correct to the nearest degree.
圖：
http://i600.photobucket.com/albums/tt87/roastchickens/94fb3c4e.jpg?t=1234595462
A.MATHS QUESTION~~~~~~~~~~~~
2009-02-14 11:11 pm
回答 (1)
2009-02-15 2:10 am
✔ 最佳答案
Consider DPQR. By cosine law,
cosPRQ
= (QR2 + PR2 - PQ2)/(2•QR•PR)
= (92 + 82 - 62)/(2 x 9 x 8)
= 0.7569
PRQ = 40.8o
Consider DPOR. By sine law:
(sinPOQ)/8 = (sinPRQ)/15
sinPOQ = 8(sin40.8o)/15
sinPOQ = 0.3485
POQ = 20o
B
= 90o - 20o
= 70o
=
收錄日期: 2021-04-29 18:16:21
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090214000051KK00994