Question 13985: The distance of the point (3,0) from the line 
Answer by longjonsilver(2297)   (Show Source):
You can put this solution on YOUR website! the quoted line has gradient 1/2.
the line through (3,0) to this first line will have a gradient of -2 (look at my Lesson on straight lines, for the reason).
So, the second line equation is y=-2x+c... need to find c:
0 = -2(3) + c
0 = -6 + c
--> c = 6
--> equation is y=-2x+6
Right, we need to know the coordinates of th epoint where the 2 points cross...ie where the 2 lines are EQUAL...
so, we have y = (1/2)x + 1 = -2x + 6
(1/2)x = -2x + 5
x = -4x + 10
5x = 10
--> x = 2.
so from y = -2x + 6, we get
y = -2(2) + 6
y = -4 + 6
y = +2
so, point of intersection is (2,2).
So now you have 2 points (3,0) and (2,2)...find the length of that line...you do that :-)
jon.
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