Answer:The value of y is 8 if AB is perpendicular CD after using the slope formula.
What is the slope?
The ratio that y increase as x increases is the slope of a line. The slope of a line reflects how steep it is, but how much y increases as x increases. Anywhere on the line, the slope stays unchanged (the same).
It is given that:
A(9, 2), B(-1, y) C.(-5, 16) and D(-8, 11),
AB is the perpendicular CD
Using the slope formula to find the slope between A and B:
(y-2)/(-1-9)
= (y-2)/-10
(11-16)/(-8-(-5)) =
-5/(-3)
= 5/3
The perpendicular slope is -3/5
(y-2)/10=-3/5
5(y-2)=3(10)
5y-10=30
5y=40
y = 8
Thus, the value of y is 8 if AB is perpendicular CD after using the slope formula.