Final answer:
To prove that the diagonals of parallelogram ABCD bisect each other using coordinate geometry, one determines vertex C's coordinates and then shows the midpoints of diagonals AC and BD are the same.
Step-by-step explanation:
To complete the coordinate proof that the diagonals of parallelogram ABCD bisect each other, we need to determine the coordinates of vertex C and then show that the midpoints of diagonals AC and BD are the same.
To begin, since AD is parallel to BC and AB is parallel to DC, the coordinates of C must be the sum of the vectors AB and AD, which gives us C(a+c, b). By calculating the midpoints of AC and BD, we find that both midpoints are ((a+c)/2, b/2).
Thus, we have shown that the midpoints for both diagonals are the same, which concludes the proof that the diagonals of parallelogram ABCD bisect each other.