Rectangle ABCD as vertices A(9, 3), B(9, 6), and C(2, 6). What are the coordinates of point D?

1 Answer
Jan 21, 2017

D(2;3)D(2;3)

Explanation:

Let's calculate the middle point of the diagonal AC: it will be te middle point of the diagonal BD.

M=((x_A+x_C)/2;(y_A+y_C)/2)=((9+2)/2;(3+6)/2)=(11/2;9/2)M=(xA+xC2;yA+yC2)=(9+22;3+62)=(112;92)

and

M=((x_B+x_D)/2;(y_B+y_D)/2)=((9+x_D)/2;(6+y_D)/2)M=(xB+xD2;yB+yD2)=(9+xD2;6+yD2)

then

(9+x_D)/2=11/2; x_D=29+xD2=112;xD=2

and

(6+y_D)/2=9/2; y_D=36+yD2=92;yD=3

D(2;3)D(2;3)