Question

B is the midpoint of AC and E is the midpoint of BD. If A(-9,-4), C(-1,6) and E(-4,-3), find the coordinates of D

Answer 1

9514 1404 393

Answer:

D = (-3, -1)

Explanation:

B is the midpoint of AC, so ...

B = (A +C)/2

E is the midpoint of BD, so ...

E = (B +D)/2

Solving for D, we have ...

2E -B = D = 2E -(A +C)/2

D = 2(-4, -3) -((-9, -4) +(-1, 6))/2 = (-8, -6) -(-10, 2)/2)

D = (-8 +5, -6 -1)

D = (-3, -7)