## Migitmack Group Title One endpoint of a segment is (12,-8). The midpoint is (3,18). Find the coordinates of the other endpoint. one year ago one year ago

1. CliffSedge Group Title

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?

2. Migitmack Group Title

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

3. CliffSedge Group Title

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

4. CliffSedge Group Title

|dw:1346614090275:dw|

5. CliffSedge Group Title

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

6. Migitmack Group Title

1 sec

7. cathyangs Group Title

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

8. Migitmack Group Title

Whats M

9. CliffSedge Group Title

M=midpoint.

10. Migitmack Group Title

I don't understand

11. Migitmack Group Title

i did the formula

12. Migitmack Group Title

but I where is the M

13. CliffSedge Group Title

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|

14. Migitmack Group Title

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

15. CliffSedge Group Title

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.

16. Migitmack Group Title

Is X 9 or 7?

17. CliffSedge Group Title

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

18. CliffSedge Group Title

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.

19. Migitmack Group Title

For Y its going to be 5?

20. Migitmack Group Title

@CliffSedge

21. Migitmack Group Title

@Cliffsedge yo is it 5 for y?

22. CliffSedge Group Title

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

23. CliffSedge Group Title

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