Understanding the Relationship Between Area and Diameter

Oct 13, 2025 by wbrum.org 53 views

Understanding the Relationship Between Area and Diameter

The area of a circle is directly proportional to the square of its diameter. This relationship can be expressed using the formula:

A = πr^2

where A is the area of the circle, π (pi) is a mathematical constant approximately equal to 3.14159, and r is the radius of the circle.

Finding the Radius from the Given Area

Given that the area of the circle is 706.9 in², we can use the formula to find the radius:

706.9 = πr^2

To solve for r, we can divide both sides of the equation by π:

r^2 = 706.9 / π

r^2 = 706.9 / 3.14159

r^2 = 225.0

Taking the square root of both sides of the equation gives us the radius:

r = √225.0

r = 15.0

Finding the Diameter from the Radius

Now that we have the radius, we can find the diameter by multiplying the radius by 2:

diameter = 2r

diameter = 2(15.0)

diameter = 30.0

Therefore, the diameter of the circle with an area of 706.9 in² is 30 inches.

Conclusion

In this article, we used the formula for the area of a circle to find the radius and then used the radius to find the diameter. We found that the diameter of the circle with an area of 706.9 in² is 30 inches.

Answer

The correct answer is B. 30 inches.

Additional Information

The formula for the area of a circle is:

A = πr^2

where A is the area of the circle, π (pi) is a mathematical constant approximately equal to 3.14159, and r is the radius of the circle.

The formula for the diameter of a circle is:

diameter = 2r

where r is the radius of the circle.

Practice Problems

Find the diameter of a circle with an area of 113.1 in².
Find the radius of a circle with an area of 254.5 in².
Find the diameter of a circle with a radius of 8.5 inches.

Solutions

The diameter of the circle with an area of 113.1 in² is 10 inches.
The radius of the circle with an area of 254.5 in² is 15.5 inches.
The diameter of the circle with a radius of 8.5 inches is 17 inches.
Circle Diameter Q&A =====================

Frequently Asked Questions About Circle Diameter

Q: What is the formula for finding the diameter of a circle?

A: The formula for finding the diameter of a circle is:

diameter = 2r

where r is the radius of the circle.

Q: How do I find the radius of a circle if I know its area?

A: To find the radius of a circle if you know its area, you can use the formula:

A = πr^2

where A is the area of the circle, π (pi) is a mathematical constant approximately equal to 3.14159, and r is the radius of the circle.

Q: What is the relationship between the area and diameter of a circle?

A: The area of a circle is directly proportional to the square of its diameter. This means that as the diameter of a circle increases, its area increases at a faster rate.

Q: Can I find the diameter of a circle if I know its circumference?

A: Yes, you can find the diameter of a circle if you know its circumference. The formula for the circumference of a circle is:

C = 2πr

where C is the circumference of the circle, π (pi) is a mathematical constant approximately equal to 3.14159, and r is the radius of the circle.

Q: How do I find the radius of a circle if I know its circumference?

A: To find the radius of a circle if you know its circumference, you can use the formula:

C = 2πr

where C is the circumference of the circle, π (pi) is a mathematical constant approximately equal to 3.14159, and r is the radius of the circle.

Q: What is the difference between the diameter and radius of a circle?

A: The diameter of a circle is the distance across the circle passing through its center, while the radius is the distance from the center of the circle to its edge.

Q: Can I find the diameter of a circle if I know its area and circumference?

A: Yes, you can find the diameter of a circle if you know its area and circumference. You can use the formulas:

A = πr^2

C = 2πr

to find the radius and then use the formula:

diameter = 2r

to find the diameter.

Q: What are some real-world applications of finding the diameter of a circle?

A: Finding the diameter of a circle has many real-world applications, including:

Calculating the area of a circular room or building
Determining the size of a circular pipe or tube
Finding the circumference of a circular object
Calculating the volume of a circular container or tank

Conclusion

In this article, we have answered some frequently asked questions about circle diameter, including how to find the diameter of a circle if you know its area, circumference, or radius. We have also discussed the relationship between the area and diameter of a circle and some real-world applications of finding the diameter of a circle.