唔識做功課16
2013-12-21 11:10 pm
Find the value of k if the line joining the points ( 7,9 ) and ( k,3 ) is perpendicular to a line with slope 4/3.
回答 (2)
2013-12-21 11:41 pm
✔ 最佳答案
slope of line jointing (7,9) and (k,3) :(9-3)/(7-k) = 6/(7-k)
it should = -(3/4) since it is perpendicular to a line with slope 4/3, the product of their slopes must = -1.
therefore : 6/(7-k) = -(3/4)
-24 = (3)(7-k)
-24 = 21 - 3k
3k = 21 + 24
3k = 45
k = 15
checking :
(9-3)/(7-15) = 6/(-8) = -3/4
(-3/4)(4/3) = -1
收錄日期: 2021-04-13 19:51:35
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20131221000051KK00082