Difference between revisions of "Radius"
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| − | 1. | + | 1. [[Diameter]]: <math> d = 2 r </math> |
| − | The diameter is the longest chord | + | The diameter is the longest [[chord]] in a circle. It is usually expressed by D or d. |
| − | 2. | + | 2. [[Circumference]] ([[perimeter]]): <math> C = 2 \pi r </math> |
| − | The circumference is the distance around a circle. It is usually represented by C. | + | The circumference is the [[distance]] around a circle. It is usually represented by C. |
| − | 3. | + | 3. [[Area]]: <math> S\:\text{or}\:A = \pi r^2 </math> |
The area of a circle is the amount of space it occupies. It is usually denoted using S or A. | The area of a circle is the amount of space it occupies. It is usually denoted using S or A. | ||
Latest revision as of 22:49, 5 January 2023
The radius of a circle is the distance from the center to any point on the circle. Identical definitions hold for the sphere and hypersphere. The plural form of radius is radii.
The radius of a circle is often denoted using R or r.
![[asy]size(150); pair O=origin, P=dir(30); D(unitcircle); D(O--P); MP("O",D(O),NNW); MP("P",D(P),NE); MP("r",midpoint(O--P),NNW);[/asy]](http://latex.artofproblemsolving.com/d/1/2/d12fe09918e0b15cda7055e7772d2844cedbc269.png)
Links to other key terms
1. Diameter: 
The diameter is the longest chord in a circle. It is usually expressed by D or d.
2. Circumference (perimeter): 
The circumference is the distance around a circle. It is usually represented by C.
3. Area: 
The area of a circle is the amount of space it occupies. It is usually denoted using S or A.
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