Find a line intersecting a known line at right angle, given a point

Question

This is basic graphics geometry and/or trig, and I feel dumb for asking it, but I can\'t remember how this goes. So:

1. I have a line defined by two points (x1, y1

Answer 1

Based on this article

let x1, x2, y1, y2, slope, xp, yp, m, x, y
x1 = 0
y1 = 0 
x2 = 50
y2 = -50
xp = 50
yp = 0

slope = (y1 - y2) / (x1 - x2)
m = -1 / slope
x = (m * xp - yp - slope * x1 + y1) / (m - slope)
y = m * x - m * xp + yp

console.log('x: ', x, ', y: ', y )