A median intersects at the midpoint of the opposite length. The midpoint is:
x,m = (4+-2)/2 = 1
y,m = (-1+7)/2 = 3
The midpoint is at (1,3). With this point and point R(9,9), the equation would be:
y = mx + b, where
m = (9 - 3)/(9 - 1) = 0.75
b is the y-intercept
Substituting any point,
3 = 0.75(1)+b
b = 2.25
Thus, the equation for the median is:
y = 0.75x + 2.25
