How do I find the x and y values algebraically of the fourth coordinate of a parallelogram if I know the other 3 points?
TYIA
Hi
If you know the coordinates of A, B, C and you want to find the coordinates of D such that ABCD is a parallelogram then you can use the vector relation
$\displaystyle \overrightarrow{AB} = \overrightarrow{DC}$ which leads to
$\displaystyle x_B - x_A = x_C - x_D$
$\displaystyle y_B - y_A = y_C - y_D$
from which you can find the coordinates of D