Very Easy Math
2009-09-22 1:27 pm
Triangle PQR is a 30-60-90 triangle with right angle Q and longer leg PQ. Find the possible coordinates of R if P(-4,1) and Q(6,1).
回答 (1)
2009-09-22 7:20 pm
✔ 最佳答案
As Q is right angle，Therefore
ArcTan(Rq / PQ ) = 30 or ArcTan(Rq / PQ ) = 60
For ArcTan(RQ / PQ ) = 30
RQ / PQ = 1 / [Sqrt(3)]
PQ = 10
So RQ = 10 / [Sqrt(3)]
Therefore, R = 1+10 / [Sqrt(3)] or R= 1- 10 / [Sqrt(3)]
For ArcTan(RQ / PQ ) = 60
RQ / PQ = [Sqrt(3)]
PQ = 10
So RQ = 10 * [Sqrt(3)]
Therefore, R = 1+10 * [Sqrt(3)] or R= 1- 10 * [Sqrt(3)]
Finally, R = 6.773, -4.773, 18.321 -16.321
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原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090922000051KK00172