What is the slope of the line perpendicular to # y=1/3x-23 #?
If you treat the slope of the equation as a change in y over change in x, you can treat it like a triangle with sides of 1,3, and
The angle that the line makes with a horizontal is
Adding 90 degrees to this gives you a perpendicular angle, 108.435.
Take the tangent of 108.435 and you get -3