00:01
Given e is at negative 6y, f is at 6, 5, g is at 14, 11, and h is at 8, negative 13, we want to find the value of y so that ef is perpendicular to gh.
00:20
So in order for lines to be perpendicular, we need to have opposite reciprocal slopes.
00:25
Opposite as in sine, one is positive, one is negative, and reciprocal is that fraction flipped upside down.
00:32
So if i start with two -thirds, my opposite reciprocal slope would be negative three -halves.
00:41
So we're going to start by finding the slope of gh, and slope is y2 minus y1 over x2 minus x1.
00:54
I'm going to go ahead and label my points here.
00:56
Here's my x1, y1, my x2, y2.
01:00
Which one's your y's or your 1's and which one's your 2's does not matter, as long as your 1's are together on the same point and your 2's are together.
01:07
I'm going to go ahead and substitute y2 is negative 13 minus y1 is 11 over x2, which is 8, minus x1, which is 14.
01:18
Negative 13 minus 11 is negative 24.
01:21
8 minus 14 is negative 6.
01:24
Negative 24 over negative 6 is 4.
01:28
So now we're going to figure out what is the parallel slope.
01:33
And the parallel slope, since this is a positive 4, it's positive, so we're going to have negative.
01:39
4 could be rewritten as 4 over 1, so the reciprocal is 1 4th...