For line #ST#, the coordinates of point #T# are T(0,4). The midpoint of ST is (5, -8). What are the coordinates of point #S#?

1 Answer
Jan 18, 2018

The coordinates of point #S(x,y)# is #(10,-20)#

Explanation:

The coordinates of the point dividing the line segment joining

# (x_1, y_1) and (x_2, y_2)# in the ratio #m : n# internally is given

by # x=(mx_2+nx_1)/(m+n),y=(my_2+ny_1)/(m+n)# Here

#m=1 , n=1 , x_2=0 , y_2=4 , x=5 , y= -8 ;#

# x_1= ? , y_1=? :. 5= (1*0+1*x_1)/(1+1):. x_1=5*2=10#

#-8= (1*4+1*y_1)/(1+1):. y_1=-16-4=-20#

Hence the coordinates of point #S(x,y)# is #(10,-20)# [Ans]