# How to Use the Midpoint Formula to Find the Other Endpoint of a Line Segment?

• MHB
In summary: I didn't use LaTeX because the original post did not! Here:Call the other endpoint $(x_2, y_2)$. Then $x_m= (x_1+ x_2)/2$ so $2x_m= x_1+ x_2$and $x_2= 2x_m- x_1$. Similarly $y2= 2y_m- y_1$.$x_2= 2(4)- 1= 8- 1= 7$$y_2= 2(-1)- (-2)= -2+ 2= 0$.$(x_2, y_2)= (7, -0)$. Check
53. A line segment has (x_1, y_1) as one endpoint and (x_m, y_m) as its midpoint. Find the other endpoint (x_2, y_2) of the line segment in
terms of x_1, y_1, x_m, and y_m.

54. Use the result of Exercise 53 to find the endpoint (x_2, y_2) of each line segment with the given endpoint (x_1, y_1) and midpoint (x_m, y_m).

(a) (x_1, y_1) = (1, −2)
(x_m, y_m) = (4, −1)

(b) (x_1, y_1) = (−5, 11)
(x_m, y_m) = (2, 4)

I need help with 53 and 54.

Beer soaked query follows.
53. A line segment has (x_1, y_1) as one endpoint and (x_m, y_m) as its midpoint. Find the other endpoint (x_2, y_2) of the line segment in
terms of x_1, y_1, x_m, and y_m.

54. Use the result of Exercise 53 to find the endpoint (x_2, y_2) of each line segment with the given endpoint (x_1, y_1) and midpoint (x_m, y_m).

(a) (x_1, y_1) = (1, −2)
(x_m, y_m) = (4, −1)

(b) (x_1, y_1) = (−5, 11)
(x_m, y_m) = (2, 4)

I need help with 53 and 54.
What have you done so far?

53. A line segment has (x_1, y_1) as one endpoint and (x_m, y_m) as its midpoint. Find the other endpoint (x_2, y_2) of the line segment in
terms of x_1, y_1, x_m, and y_m.
Call the other endpoint (x_2, y_2). Then x_m= (x_1+ x_2)/2 so 2x_m= x_1+ x_2 and x_2= 2x_m- x_1. Similarly y2= 2y_m- y_1.

54. Use the result of Exercise 53 to find the endpoint (x_2, y_2) of each line segment with the given endpoint (x_1, y_1) and midpoint (x_m, y_m).

(a) (x_1, y_1) = (1, −2)
(x_m, y_m) = (4, −1)
x_2= 2(4)- 1= 8- 1= 7
y_2= 2(-1)- (-2)= -2+ 2= 0.
(x_2, y_2)= (7, -0). Check: ((7+1)/2, (-2- 0)/2)= (8/2, -2/2)= (4, -1).

(b) (x_1, y_1) = (−5, 11)
(x_m, y_m) = (2, 4)

I need help with 53 and 54.
Why don't you try the last one?

Country Boy said:
Call the other endpoint (x_2, y_2). Then x_m= (x_1+ x_2)/2 so 2x_m= x_1+ x_2 and x_2= 2x_m- x_1. Similarly y2= 2y_m- y_1.x_2= 2(4)- 1= 8- 1= 7
y_2= 2(-1)- (-2)= -2+ 2= 0.
(x_2, y_2)= (7, -0). Check: ((7+1)/2, (-2- 0)/2)= (8/2, -2/2)= (4, -1).Why don't you try the last one?

You said:

"Call the other endpoint (x_2, y_2). Then x_m= (x_1+ x_2)/2 so 2x_m= x_1+ x_2 and x_2= 2x_m- x_1. Similarly y2= 2y_m- y_1."

m++
You said:

"Call the other endpoint (x_2, y_2). Then x_m= (x_1+ x_2)/2 so 2x_m= x_1+ x_2 and x_2= 2x_m- x_1. Similarly y2= 2y_m- y_1."

There is NO "2x" in what I wrote. If you mean "2x_m", multiply both sides of x_m= (x_1+ x_2)/2 by 2.

Beer soaked ramblings follow.
You said:

"Call the other endpoint (x_2, y_2). Then x_m= (x_1+ x_2)/2 so 2x_m= x_1+ x_2 and x_2= 2x_m- x_1. Similarly y2= 2y_m- y_1."

Fourteen years of Precalculus review and you're still stumped by the midpoint formula?
I can see that your quest for Calculus understanding will be a very rough and even longer ride.
For someone who once pretended he's on his way to mastering Calculus as https://mathhelpboards.com/members/harpazo.8631/, it is disappointing to see you struggling once again with basic stuff.

Maybe you can see this more clearly if Countryboy decided to give his excellent answer in LaTex.
Too hammered right now to do it, so see a somewhat similar application of your present dilemma at https://mathforums.com/threads/symmetrical-line.356080/

But then again, I might already be in your prestigious Ignore List and you might not see this at all.

I didn't use LaTeX because the original post did not! Here:

https://mathhelpboards.com/goto/post?id=124850
53. A line segment has $(x_1, y_1)$ as one endpoint and $(x_m, y_m)$ as its midpoint. Find the other endpoint $(x_2, y_2)$ of the line segment in
terms of $x_1$, $y_1$, $x_m$, and $y_m$.
Call the other endpoint $(x_2, y_2)$. Then $x_m= (x_1+ x_2)/2$ so $2x_m= x_1+ x_2$and $x_2= 2x_m- x_1$. Similarly $y2= 2y_m- y_1$.

54. Use the result of Exercise 53 to find the endpoint $(x_2, y_2)$ of each line segment with the given endpoint $(x_1, y_1)$ and midpoint $(x_m, y_m)$.

(a) $(x_1, y_1) = (1, −2)$
$(x_m, y_m) = (4, −1)$
$x_2= 2(4)- 1= 8- 1= 7$
$y_2= 2(-1)- (-2)= -2+ 2= 0$.
(x_2, y_2)= (7, -0). Check: ((7+1)/2, (-2- 0)/2)= (8/2, -2/2)= (4, -1).

Last edited:
Country Boy said:
I didn't use LaTeX because the original post did not! Here:Call the other endpoint $(x_2, y_2)$. Then $x_m= (x_1+ x_2)/2$ so $2x_m= x_1+ x_2$and $x_2= 2x_m- x_1$. Similarly $y2= 2y_m- y_1$.$x_2= 2(4)- 1= 8- 1= 7$
$y_2= 2(-1)- (-2)= -2+ 2= 0$.
(x_2, y_2)= (7, -0). Check: ((7+1)/2, (-2- 0)/2)= (8/2, -2/2)= (4, -1).

Nicely done. I thank you.

Beer soaked ramblings follow.
Nicely done. I thank you.
Translation: I love cajoling members into doing my work without showing any kind of effort whatsoever on my part.

You're such a sweetheart!

## 1. What is the Midpoint Formula?

The Midpoint Formula is a mathematical equation used to find the midpoint between two points on a graph. It is represented as (x1 + x2)/2, (y1 + y2)/2.

## 2. How do you use the Midpoint Formula?

To use the Midpoint Formula, you first need to identify the coordinates of the two points you want to find the midpoint between. Then, plug those coordinates into the formula (x1 + x2)/2, (y1 + y2)/2 and solve for the midpoint.

## 3. What is the significance of the Midpoint Formula?

The Midpoint Formula is significant because it allows us to find the exact center point between two given points on a graph. This can be useful in many real-life applications, such as finding the center of a shape or determining the location of a point on a map.

## 4. Can the Midpoint Formula be used in any coordinate system?

Yes, the Midpoint Formula can be used in any coordinate system, whether it is a Cartesian plane, polar coordinates, or any other system. As long as you have the coordinates of two points, you can use the formula to find the midpoint between them.

## 5. Are there any limitations to the Midpoint Formula?

One limitation of the Midpoint Formula is that it only works for finding the midpoint between two points. It cannot be used to find the midpoint between three or more points. Additionally, the formula assumes a straight line between the two points, so it may not accurately represent the midpoint in curved or nonlinear situations.

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