Question

If point C is the midpoint of AB, what is the coordinate of point B?

Answer 1

A(xa, ya)
B(xb,yb)
C(xc,yc)

\[(xa + xb)/2 = xc; (ya+yb)/2 = yc => xb = 2xc - xa, yb = 2yc - ya\]

Answer 2

I'm confused.

Answer 3

(–3, 3)








(–2, 1)








(–4, 4)








(–4, 1)

Answer 4

those are the answer choices.

Answer 5

yep, but there aren't any coordinates...maybe you've mistaken the picture with the text? :)

Answer 6

my bad haha

Answer 7

i think that is wrong one too...that is the picture for distance of AB i guess :) here you;ll have one line, A and B on the ends, and C in the middle, as the text says

Answer 8

but, nevermind, i can give you instructions..A has x coordinate, so does B. to get x coordinate of C, you take Xa + Xb and divide that sum with 2. Same for y coordinate :)

Answer 9

nope that's the right pic. AB is supposed to have a line over it. like this:

Answer 10

i just didn't know how to type it when asking the question

Answer 11

\[A(5,5), B(x _{b}, y _{b}), C(1,4)\]

Since C is midpoint of A nd B, you use this expressions to find coordinates:
\[x _{c} = (x _{a} + x _{b}) / 2\]
\[y _{c} = (y _{a} + y _{b}) / 2\]

Therefore:
\[x _{a} = 5, y _{a} =5\]
\[x _{c} = 1, y _{c} = 4\]

Replace it in the expression above:
\[1 = (5 + x _{b}) / 2\]
\[2 = 5 + x _{b}\]
\[x _{b} = 2 - 5 = -3\]

Analogue for y coordinate:
\[4 = (5 + y _{b}) / 2\]
\[8 = 5 + y _{b}\]
\[y _{b} = 8 - 5 = 3\]

So, te answer is (-3,3)

Answer 12

the*