Ok I will show my work in the comments
I think it’s seventy five
The perpendicular line would have a slope of 1/3.
Perpendicular lines have opposite and reciprocal slopes.
To do the opposite, take the original slope (-3) and change the sign (3).
To do the reciprocal, take the slope we changed (3) and flip it as a fraction (1/3).
This gives us a new slope of 1/3.
