Answer:
11.18
Step-by-step explanation:
For this case we have that by definition, the equation of a line of the slope-intersection form is given by:

Where:
m: It is the slope of the line
b: It is the cut point with the y axis
By definition, if two lines are perpendicular then the product of their slopes is -1.
If we have: 

Thus, the equation is of the form:

We substitute the point:

Finally, the equation is:

Answer:

Y=10. Hopefully this picture explains it