Calculating Distances for Each Point

Oct 13, 2025 by wbrum.org 17 views

Introduction

The equation of a circle is a fundamental concept in mathematics, and it is essential to understand how to work with it to solve various problems. In this article, we will explore the equation of a circle, specifically the equation ${(x+1)^2+(y-3)^2=16}$ , and learn how to calculate the distance from the center of the circle to each point in a given list. We will also discuss what these distances tell us about whether each point is inside, on, or outside the circle.

The Equation of a Circle

The general equation of a circle with center ${(h,k)}$ and radius ${r}$ is given by:

${(x-h)^2+(y-k)^2=r^2}$

In our case, the equation of the circle is:

${(x+1)^2+(y-3)^2=16}$

By comparing this equation with the general equation of a circle, we can see that the center of the circle is ${(-1,3)}$ and the radius is ${\sqrt{16}=4}$ .

Calculating Distances

To calculate the distance from the center of the circle to each point in the list, we will use the distance formula:

${d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}}$

where ${(x_1,y_1)}$ is the center of the circle and ${(x_2,y_2)}$ is the point in question.

Example Points

Let's consider the following points:

Point	x-coordinate	y-coordinate
A	-2	2
B	0	0
C	2	2
D	4	4

Calculating Distances for Each Point

Point A

To calculate the distance from the center of the circle to point A, we will use the distance formula:

${d_A=\sqrt{(-2-(-1))^2+(2-3)^2}=\sqrt{1+1}=\sqrt{2}}$

Point B

To calculate the distance from the center of the circle to point B, we will use the distance formula:

${d_B=\sqrt{(0-(-1))^2+(0-3)^2}=\sqrt{1+9}=\sqrt{10}}$

Point C

To calculate the distance from the center of the circle to point C, we will use the distance formula:

${d_C=\sqrt{(2-(-1))^2+(2-3)^2}=\sqrt{9+1}=\sqrt{10}}$

Point D

To calculate the distance from the center of the circle to point D, we will use the distance formula:

${d_D=\sqrt{(4-(-1))^2+(4-3)^2}=\sqrt{25+1}=\sqrt{26}}$

Interpretation of Distances

Now that we have calculated the distances from the center of the circle to each point, let's interpret what these distances tell us about whether each point is inside, on, or outside the circle.

Point A: The distance from the center of the circle to point A is ${\sqrt{2}}$ . Since this distance is less than the radius of the circle (4), point A is inside the circle.
Point B: The distance from the center of the circle to point B is ${\sqrt{10}}$ . Since this distance is greater than the radius of the circle (4), point B is outside the circle.
Point C: The distance from the center of the circle to point C is ${\sqrt{10}}$ . Since this distance is greater than the radius of the circle (4), point C is outside the circle.
Point D: The distance from the center of the circle to point D is ${\sqrt{26}}$ . Since this distance is greater than the radius of the circle (4), point D is outside the circle.

Conclusion

In conclusion, we have learned how to calculate the distance from the center of a circle to each point in a given list using the distance formula. We have also discussed how to interpret these distances to determine whether each point is inside, on, or outside the circle. By understanding the equation of a circle and calculating distances, we can solve various problems in mathematics and real-world applications.

References

[1] "Equation of a Circle." Math Open Reference, mathopenref.com/circle.html.
[2] "Distance Formula." Math Is Fun, mathisfun.com/algebra/distance-formula.html.

Introduction

In our previous article, we explored the equation of a circle and learned how to calculate the distance from the center of the circle to each point in a given list. In this article, we will answer some frequently asked questions about circles and distances to help you better understand this topic.

Q&A

Q: What is the equation of a circle?

A: The equation of a circle is a mathematical formula that describes the shape of a circle. It is typically written in the form:

${(x-h)^2+(y-k)^2=r^2}$

where ${(h,k)}$ is the center of the circle and ${r}$ is the radius.

Q: How do I calculate the distance from the center of a circle to a point?

A: To calculate the distance from the center of a circle to a point, you can use the distance formula:

${d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}}$

where ${(x_1,y_1)}$ is the center of the circle and ${(x_2,y_2)}$ is the point in question.

Q: What does the distance from the center of a circle to a point tell me?

A: The distance from the center of a circle to a point tells you whether the point is inside, on, or outside the circle. If the distance is less than the radius of the circle, the point is inside the circle. If the distance is equal to the radius of the circle, the point is on the circle. If the distance is greater than the radius of the circle, the point is outside the circle.

Q: How do I determine whether a point is inside, on, or outside a circle?

A: To determine whether a point is inside, on, or outside a circle, you can calculate the distance from the center of the circle to the point using the distance formula. If the distance is less than the radius of the circle, the point is inside the circle. If the distance is equal to the radius of the circle, the point is on the circle. If the distance is greater than the radius of the circle, the point is outside the circle.

Q: What is the significance of the radius of a circle?

A: The radius of a circle is the distance from the center of the circle to any point on the circle. It is a critical component of the equation of a circle and is used to determine whether a point is inside, on, or outside the circle.

Q: Can I use the distance formula to calculate the distance between two points on a circle?

A: Yes, you can use the distance formula to calculate the distance between two points on a circle. However, you will need to use the coordinates of the two points to calculate the distance.

Q: What is the relationship between the distance from the center of a circle to a point and the radius of the circle?

A: The distance from the center of a circle to a point is related to the radius of the circle. If the distance is less than the radius, the point is inside the circle. If the distance is equal to the radius, the point is on the circle. If the distance is greater than the radius, the point is outside the circle.

Conclusion

In conclusion, we have answered some frequently asked questions about circles and distances to help you better understand this topic. By understanding the equation of a circle, calculating distances, and determining whether points are inside, on, or outside a circle, you can solve various problems in mathematics and real-world applications.

References

[1] "Equation of a Circle." Math Open Reference, mathopenref.com/circle.html.
[2] "Distance Formula." Math Is Fun, mathisfun.com/algebra/distance-formula.html.