what is the formula for finding point A on a line graph when only the coordinates of the midpoint and point B are known?

thanks

Walthamx Nov 26, 2017

#1**+1 **

Remember that to find the x coordinate of the midpoint we add the x coordinates of the two endpoints and divide by 2 and do the same for the y coordinates to find the y coordinate of the midpoint

So...we have that

[ Ax + Bx ] / 2 = x coordinate of the midpoint

So.......

Ax + Bx = 2 * x coordinate of the midpoint

Ax = 2 * x coordinate of the midpoint - Bx

Similarly

[Ay + By ] / 2 = y coordinate of the midpoint

Ay + By = 2 * y coordinate of the midpoint

Ay = 2 * y coordinate of the midpoint - By

CPhill Nov 26, 2017