Given Triangle $DEF$ with vertices $$D(-2,6),E(7,3), \text{ and } F (2,-3)$$ find:
a) the equation of the altitude from vertex $E$ in standard form (include y=mx+b)
b) Find where this altitude in a) intersects side $DF.$
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What have you done so far? – Théophile Apr 28 '15 at 23:20
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I am completely lost and I have no idea on what to do. Thanks. – a s Apr 28 '15 at 23:22
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please help and thanks. – a s Apr 28 '15 at 23:27
1 Answers
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i will give you some hints.
(a) can you find the slope of $DF?$
(b) let $P$ be the foot of the perpendicular from $E$ to $DF.$ what is the relation between the slopes of $EP$ and $DF?$
(c) you know the slope of $EP$ and the point $E=(7,3).$ can you write the equation of $EP?$
(d) can you also write the equation of the $DF?$
(e) can you solve the two simultaneous equations in $(c)$ and $(d)?$
abel
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Okay so I got 4x-9y+9=0 or y=4/9+3/2 which is ALMOST correct. The correct answer would be 4x+9y+1=0. I can't find where I went wrong. Thanks :D – a s Apr 28 '15 at 23:58
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i think i found it; I had to find slope DF, then perpendicular passing through (7,3). Next, I had to use linear systems to find point of intersection. thanks a lot. – a s Apr 29 '15 at 00:21
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