Given point A(-6, 7) is the midpoint B(A, 4) and point C(0, b). What is the values of a and b?
xC = ( xA + xB ) / 2
yC = ( yA + yB ) / 2
In this case:
xA = - 6 , yA = 7
xB = a , yB = 4
xC = 0
yC = b
xC = ( xA + xB ) / 2
0 = ( xA + xB ) / 2
( - 6 + xB ) / 2 = 0
Multiply both sides by 2
- 6 + xB = 0
Add 6 to both sides
xB = 6
xB = a
a = 6
yC = ( yA + yB ) / 2
Since yC = b
b = ( 7 + 4 ) / 2
b = 11 / 2