ABCD is a parallelogram. The coordinates of D is not known. Let D(x,y).

Since in the parallelogram AB||CD, slope of AB=slope of DC.

Slope of AB=(3-4)/(1-(-2)) = 1/3

Slope of DC = (y-(-1))/(x-4) = (y+1)/(x-4)

Equating the two slopes we get:

(y+1)/(x-4) = 1/3 cross multiply

3(y + 1) = x - 4

Similarly, equating the slopes of the other two parallel sides AD and BC we get:

(y-4)/(x-(-2))=(-1-3)/(4-1)

(y-4)/(x+2) = -4/3 cross multiply

3(y-4) = (-4)(x+2)

By solving the system of equations:

3(y + 1) = x - 4

3(y - 4) = (-4)(x + 2)

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x = 2.2

y = -1.6

The coordinates of D are (2.2, -1.6)