Question

find the equation of an altitude from A in triangle ABC. A(2,8) B(-6,-4) C(8,0)

thank you!

Answer 1

First find the slope of the line through points B and C

Answer 2

Tell me what you get

Answer 3

-8,-12 and 6,-8

Answer 4

how are you getting that

Answer 5

the slope is just a single number btw

Answer 6

idk...

Answer 7

use the slope formula

m = (y2 - y1)/(x2 - x1)

Answer 8

so in this case, you would get

m = (y2 - y1)/(x2 - x1)

m=(0-(-4))/(8-(-6))

m = (0+4)/(8+6)

m = 4/14

m = 2/7

Answer 9

2/3 and -.75

Answer 10

That's the slope of the line through B and C

Answer 11

see how I got that?

Answer 12

oh

Answer 13

so what's the perpendicular slope

Answer 14

ya but what about the altitude?

Answer 15

we're getting there (slowly but surely)

what's the perpendicular slope

Answer 16

7/2?

Answer 17

close

Answer 18

but you have to change the sign as well, so it's negative

Answer 19

so we know this

the altitude has a slope of -7/2

the altitude goes through the point (2,8)

do you see how to use this info to find the equation?