The slope of the line perpendicular to y = 3/4 x is -4/3 because the slope of lines perpendicular to each other need to be negative reciprocals of each other.
y=3/4x as you know y = mx + b so slope = m in this case y=3/4x slope m = 3/4 perpendicular lines, slope is opposite and reciprocal so perpendicular line has slope m = -4/3
