Here's the question you clicked on:
Migitmack
One endpoint of a segment is (12,-8). The midpoint is (3,18). Find the coordinates of the other endpoint.
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?
Can U just tell me I am kinda lazy -_-
Nope. Stop being lazy. I will draw a picture for you though.
|dw:1346614090275:dw|
Your other option is to use the formula: \[M(x,y)=\left(\frac{x_1+x_2}{2},\frac{y_1+y_2}{2}\right).\]
@Migitmack , @CliffSedge is explaining it quite well. Openstudy is supposed to help you study, it's not an answer-generator.
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) |dw:1346614542836:dw|
I hoy (7.5, -72)?!!!!!?! I think I did something wrong
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.
The formula would look like this: \[M(3,18)=(\frac{12+x}{2},\frac{-8+y}{2}).\] Handle the x and y equations separately: \[3=\frac{12+x}{2}, \space 18=\frac{-8+y}{2}\]
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.
For Y its going to be 5?
@Cliffsedge yo is it 5 for y?
Why do you think 5 for y? How did you get that number?
I'm guessing you're finding the midpoint of (3,18) and (12,-8) but (3,18) *is* the midpoint.