Understanding Distances in a Coordinate Plane

Oct 13, 2025 by wbrum.org 120 views

Introduction

In geometry, the distance between two points in a coordinate plane is a fundamental concept that has numerous applications in various fields, including mathematics, physics, and engineering. The distance between two points can be calculated using the distance formula, which is derived from the Pythagorean theorem. In this article, we will explore the concept of distances between points in a coordinate plane, specifically the distances QR and PR, and find a relation between x and y such that the point (x, y) is equidistant from the points (3, 6) and (-3, 4).

Understanding Distances in a Coordinate Plane

The distance between two points (x1, y1) and (x2, y2) in a coordinate plane can be calculated using the distance formula:

d = √((x2 - x1)^2 + (y2 - y1)^2)

where d is the distance between the two points.

Calculating Distances QR and PR

To calculate the distances QR and PR, we need to know the coordinates of the points Q and R. Let's assume that the coordinates of point Q are (x, y) and the coordinates of point R are (3, 6).

The distance QR can be calculated as:

QR = √((3 - x)^2 + (6 - y)^2)

Similarly, the distance PR can be calculated as:

PR = √((-3 - x)^2 + (4 - y)^2)

Finding a Relation Between x and y

We want to find a relation between x and y such that the point (x, y) is equidistant from the points (3, 6) and (-3, 4). This means that the distances QR and PR are equal.

Set QR = PR:

√((3 - x)^2 + (6 - y)^2) = √((-3 - x)^2 + (4 - y)^2)

Squaring both sides of the equation:

(3 - x)^2 + (6 - y)^2 = (-3 - x)^2 + (4 - y)^2

Expand the squares:

9 - 6x + x^2 + 36 - 12y + y^2 = 9 + 6x + x^2 + 16 - 8y + y^2

Combine like terms:

-6x - 12y = 6x - 8y

Add 6x to both sides:

0 = 18x - 4y

Add 4y to both sides:

4y = 18x

Divide both sides by 4:

y = 4.5x

Section Formula

The section formula is a formula used to find the coordinates of a point that divides a line segment into a particular ratio. The section formula is given by:

(x, y) = ((mx2 + nx1)/(m + n), (my2 + ny1)/(m + n))

where (x1, y1) and (x2, y2) are the coordinates of the two points, and m and n are the ratios.

Finding the Point (x, y) Using the Section Formula

We want to find the point (x, y) that divides the line segment joining the points (3, 6) and (-3, 4) in the ratio 2:1.

Using the section formula:

(x, y) = ((2(-3) + 1(3))/(2 + 1), (2(4) + 1(6))/(2 + 1))

Simplify the expression:

(x, y) = ((-6 + 3)/3, (8 + 6)/3)

(x, y) = (-3/3, 14/3)

(x, y) = (-1, 14/3)

Conclusion

In this article, we explored the concept of distances between points in a coordinate plane, specifically the distances QR and PR. We found a relation between x and y such that the point (x, y) is equidistant from the points (3, 6) and (-3, 4). We also used the section formula to find the point (x, y) that divides the line segment joining the points (3, 6) and (-3, 4) in the ratio 2:1.

References

[1] Khan Academy. (n.d.). Distance Formula. Retrieved from https://www.khanacademy.org/math/geometry/geometry-basics/geometry-basics/v/distance-formula
[2] Math Open Reference. (n.d.). Section Formula. Retrieved from https://www.mathopenref.com/coordsection.html

Q: What is the distance formula?

A: The distance formula is a formula used to find the distance between two points in a coordinate plane. It is given by:

d = √((x2 - x1)^2 + (y2 - y1)^2)

where d is the distance between the two points.

Q: How do I calculate the distances QR and PR?

A: To calculate the distances QR and PR, you need to know the coordinates of the points Q and R. Let's assume that the coordinates of point Q are (x, y) and the coordinates of point R are (3, 6).

The distance QR can be calculated as:

QR = √((3 - x)^2 + (6 - y)^2)

Similarly, the distance PR can be calculated as:

PR = √((-3 - x)^2 + (4 - y)^2)

Q: What is the relation between x and y such that the point (x, y) is equidistant from the points (3, 6) and (-3, 4)?

A: To find the relation between x and y, we set QR = PR:

√((3 - x)^2 + (6 - y)^2) = √((-3 - x)^2 + (4 - y)^2)

Squaring both sides of the equation:

(3 - x)^2 + (6 - y)^2 = (-3 - x)^2 + (4 - y)^2

Expand the squares:

9 - 6x + x^2 + 36 - 12y + y^2 = 9 + 6x + x^2 + 16 - 8y + y^2

Combine like terms:

-6x - 12y = 6x - 8y

Add 6x to both sides:

0 = 18x - 4y

Add 4y to both sides:

4y = 18x

Divide both sides by 4:

y = 4.5x

Q: What is the section formula?

A: The section formula is a formula used to find the coordinates of a point that divides a line segment into a particular ratio. The section formula is given by:

(x, y) = ((mx2 + nx1)/(m + n), (my2 + ny1)/(m + n))

where (x1, y1) and (x2, y2) are the coordinates of the two points, and m and n are the ratios.

Q: How do I find the point (x, y) using the section formula?

A: To find the point (x, y) using the section formula, you need to know the coordinates of the two points and the ratio in which the line segment is divided.

Let's assume that the coordinates of the two points are (3, 6) and (-3, 4), and the ratio is 2:1.

Using the section formula:

(x, y) = ((2(-3) + 1(3))/(2 + 1), (2(4) + 1(6))/(2 + 1))

Simplify the expression:

(x, y) = ((-6 + 3)/3, (8 + 6)/3)

(x, y) = (-3/3, 14/3)

(x, y) = (-1, 14/3)

Q: What are some real-world applications of the distance formula and section formula?

A: The distance formula and section formula have numerous real-world applications in various fields, including:

Navigation: The distance formula is used to calculate the distance between two points on a map, which is essential for navigation.
Engineering: The section formula is used to find the coordinates of a point that divides a line segment into a particular ratio, which is essential for designing and building structures.
Computer Science: The distance formula and section formula are used in algorithms for solving problems related to geometry and spatial reasoning.

Q: What are some common mistakes to avoid when using the distance formula and section formula?

A: Some common mistakes to avoid when using the distance formula and section formula include:

Not squaring the terms correctly
Not adding the like terms correctly
Not simplifying the expression correctly
Not using the correct formula for the given problem

Q: How can I practice using the distance formula and section formula?

A: You can practice using the distance formula and section formula by:

Solving problems related to geometry and spatial reasoning
Using online resources and calculators to check your answers
Working with a partner or tutor to review and practice the formulas
Creating your own problems and solutions to practice the formulas

Conclusion

In this Q&A article, we covered the distance formula, section formula, and their applications in real-world scenarios. We also discussed common mistakes to avoid and provided tips for practicing the formulas.