Table of Contents

**Diameter Formula**

**Introduction:**

The diameter is a fundamental concept in geometry that is used to measure the length of a straight-line segment passing through the center of a circle or a sphere, dividing it into two equal parts. It is commonly represented by the symbol ‘d’. The diameter is twice the length of the radius of the circle or sphere, and it plays a crucial role in various calculations involving circles and spheres, such as finding the circumference, area, or volume. The diameter formula, which relates the diameter to other properties of circles or spheres, is a key tool in solving geometric problems involving these shapes.

**Definition of Diameter:**

The diameter of a circle is a line segment that passes through the center of the circle and has its endpoints on the circle. It is the longest chord in a circle.

**Diameter Formula:**

The formula to calculate the diameter of a circle is:

Diameter = 2 x Radius

Where:

“Diameter” represents the length of the diameter of the circle

“Radius” represents the distance from the center of the circle to any point on the circle’s circumference

The diameter is always twice the length of the radius. It is an essential measurement in various geometric calculations, such as finding the circumference, area, or other properties of a circle.

**Solved Examples on Diameter Formula:**

**Example 1:** A circular pizza has a diameter of 16 inches. What is the radius of the pizza?

Solution:

To find the radius, we can use the formula:

Radius = Diameter / 2

Substituting the given diameter into the formula, we have:

Radius = 16 / 2

Radius = 8 inches

Therefore, the radius of the pizza is 8 inches.

**Example 2:** A circular swimming pool has a diameter of 10 meters. Find its radius.

Solution:

To find the radius of the pool, we can rearrange the formula for the diameter:

Diameter = 2 x Radius

Dividing both sides of the equation by 2, we get:

Radius = Diameter / 2

Radius = 10 / 2

Radius = 5 meters

Hence, the radius of the swimming pool is 5 meters.

**Example 3:** A circular garden has a perimeter of 100 meters. Find the diameter of the garden.

Solution:

The perimeter of a circle is given by the formula:

Perimeter = π x Diameter

We know that the perimeter is 100 meters, so we can set up the equation:

100 = π x Diameter

To find the diameter, we can rearrange the formula:

Diameter = Perimeter / π

Plugging in the given values, we have:

Diameter = 100 / π

Using an approximation for π as 3.14, we can calculate the diameter:

Diameter ≈ 100 / 3.14 ≈ 31.85 meters

Therefore, the diameter of the garden is approximately 31.85 meters.

**Frequently Asked Questions on Diameter Formula:**

1: What is the diameter of a circle?

Answer: The diameter of a circle is a straight line segment that passes through the center of the circle and has its endpoints on the circle’s circumference. It is the longest possible chord in a circle. Diameter is a fundamental measurement in circle geometry as it determines the size and proportions of the circle.

2: What is the diameter formula of a circle?

Answer: The diameter formula of a circle is given by:

d = 2r,

where ‘d’ represents the diameter and ‘r’ represents the radius of the circle. The diameter is twice the length of the radius, meaning that if you know the radius, you can find the diameter by multiplying it by 2. Similarly, if you know the diameter, you can find the radius by dividing it by 2.

3: How is the diameter related to the radius of a circle?

Answer: The diameter of a circle is directly related to its radius. The diameter is always twice the length of the radius. Mathematically, Diameter = 2 x Radius. The radius is the distance from the center of the circle to any point on its circumference, while the diameter is the distance between two points on the circumference passing through the center.

4: What is the relationship between the diameter and circumference of a circle?

Answer: The circumference of a circle is directly related to its diameter. The formula for the circumference of a circle is Circumference = π x Diameter, where π is a mathematical constant approximately equal to 3.14. This formula shows that the circumference is directly proportional to the diameter. In other words, as the diameter of a circle increases, its circumference also increases.

5: What is the radius of a circle?

Answer: The radius of a circle is a line segment that connects the center of the circle to any point on its circumference. It is denoted by the symbol ‘r’. The radius is a fundamental measurement of a circle and is used to calculate various properties such as the diameter, circumference, and area of the circle. It represents the distance from the center of the circle to its outer boundary, and it is always half the length of the diameter.

6: What is the half of diameter of a circle called?

Answer: Half of the diameter of a circle is equal to its radius. In other words, if the diameter of a circle is denoted as “d,” then half of the diameter is equal to “d/2.” The radius of a circle is the distance from its center to any point on its circumference. So, the radius is essentially half of the diameter.

7: Can the diameter of a circle be equal to the circumference?

Answer: No, the diameter of a circle cannot be equal to the circumference. The circumference of a circle is always longer than its diameter. The ratio of the circumference to the diameter of any circle is a constant value known as π (pi), which is approximately 3.14. Therefore, the circumference will always be greater than the diameter by a factor of π.

8: How to Find Diameter from Circumference?

Answer: To find the diameter of a circle from its circumference, you can use the formula: diameter = circumference / π. Divide the circumference of the circle by the value of π (pi, approximately 3.14159) to obtain the diameter. This formula allows you to calculate the diameter directly from the known circumference of the circle.