You need to find the slope first. (-9,-4). (3,4)
-4-4= -8
-9-3 =-12. Slope is -8/-12 or 8/12 or 2/3
Perpendicular is the negative reciprocal. Or flip over the 2/3 and make it negative.
The answer is - 3/2
The missing coordinates of the parallelogram is (m + h, n).
Solution:
Diagonals of the parallelogram bisect each other.
Solve using mid-point formula:

Here 


<u>To find the missing coordinate:</u>
Let the missing coordinates by x and y.
Here 



Now equate the x-coordinate.

Multiply by 2 on both sides of the equation, we get
m + h = x
x = m + h
Now equate the y-coordinate.

Multiply by 2 on both sides of the equation, we get
n = y
y = n
Hence the missing coordinates of the parallelogram is (m + h, n).
If 0.3 = 1 then 0.9 = 3 because 0.3+0.3+0.3=the 3.
The answer u have is correct how it is