Question

One endpoint of a segment is (12,-8). The midpoint is (3,18). Find the coordinates of the other endpoint.

Answer 1

Could use the formula, but it's easy enough to just reason through it:
What number is the same distance from 3 as 12, and what number is the same distance from 18 as -8?

Answer 2

Can U just tell me I am kinda lazy -_-

Answer 3

Nope. Stop being lazy. I will draw a picture for you though.

Answer 4

Your other option is to use the formula:
\[M(x,y)=\left(\frac{x_1+x_2}{2},\frac{y_1+y_2}{2}\right).\]

Answer 5

1 sec

Answer 6

@Migitmack , @CliffSedge is explaining it quite well. Openstudy is supposed to help you study, it's not an answer-generator.

Answer 7

Whats M

Answer 8

M=midpoint.

Answer 9

I don't understand

Answer 10

i did the formula

Answer 11

but I where is the M

Answer 12

You have the coordinates for the midpoint and one other point, so rearrange the formula to solve for what you don't know. (If you want to use the formula.. I still think just doing some elementary subtraction is more straight-forward)

Answer 13

I hoy (7.5, -72)?!!!!!?! I think I did something wrong

Answer 14

Just look at the first picture I drew and ask yourself these questions:
1. 3 is halfway between 12 and what other number? That's your x.
2. 18 is halfway between -8 and what other number? That's your y.

Answer 15

Is X 9 or 7?

Answer 16

The formula would look like this:
\[M(3,18)=(\frac{12+x}{2},\frac{-8+y}{2}).\]
Handle the x and y equations separately:
\[3=\frac{12+x}{2}, \space 18=\frac{-8+y}{2}\]

Answer 17

The distance from 3 to 12 is 9, so what number is also 9 units away from 3, but in the other direction?
Use the same reasoning for y.

Answer 18

For Y its going to be 5?

Answer 19

@CliffSedge

Answer 20

@Cliffsedge yo is it 5 for y?

Answer 21

Why do you think 5 for y? How did you get that number?

Answer 22

I'm guessing you're finding the midpoint of (3,18) and (12,-8) but (3,18) *is* the midpoint.