Usually represented by the letter "D". The line segment connecting two points on the circumference and passing through the center of the circle is called the diameter of the circle, and the line segment connecting two points on the sphere and passing through the center of the sphere is called the diameter of the sphere. The diameter is the longest chord in a circle.
A straight line with a diameter is the symmetry axis of a circle. The two endpoints of the diameter are on a circle, and the center of the circle is the midpoint of the diameter. Diameter divides a circle into two parts with equal area, and the middle line segment is called diameter (each part becomes a semicircle).
Diameter is one of the important properties of a circle, which can be used to calculate its perimeter and area. Diameter is one of the basic properties of a circle, which plays an important role in many mathematical problems related to the circle, and is widely used and of great significance in geometry, physics and engineering.
The relationship between the radius and diameter of a circle
The relationship between radius and diameter of a circle is very simple and intuitive. According to the definition, the diameter is a line segment connecting two points on a circle through the center of the circle, so the length of the diameter is equal to twice the radius. In other words, the diameter is twice the radius. This relationship can be expressed by a mathematical expression: diameter =2× radius.
In practical application, the relationship between radius and diameter of a circle has many important applications. First, when calculating the circumference and area of a circle, we need to use radius or diameter.
The circumference of a circle is the sum of the distances from all points on the circle to the center of the circle, which can be expressed by the formula C=2πr or C=πd, where π is a constant, which is about equal to 3. 14 159. It can be seen from these two formulas that both diameter and radius are important parameters for calculating the circumference.
Baidu encyclopedia-diameter