![geometry - Why the perimeter of a ring is $2\pi(R+r)$ and not $2\pi(R-r)$ ? where $R$ is the bigger circle radius and $r$ is smaller circle radius - Mathematics Stack Exchange geometry - Why the perimeter of a ring is $2\pi(R+r)$ and not $2\pi(R-r)$ ? where $R$ is the bigger circle radius and $r$ is smaller circle radius - Mathematics Stack Exchange](https://i.stack.imgur.com/Zd3AN.png)
geometry - Why the perimeter of a ring is $2\pi(R+r)$ and not $2\pi(R-r)$ ? where $R$ is the bigger circle radius and $r$ is smaller circle radius - Mathematics Stack Exchange
![The circumference of two concentric rings are 88cm and 66cm respectively The width between the rings is : a) - Maths - Perimeter and Area - 14200163 | Meritnation.com The circumference of two concentric rings are 88cm and 66cm respectively The width between the rings is : a) - Maths - Perimeter and Area - 14200163 | Meritnation.com](https://s3mn.mnimgs.com/img/shared/content_ck_images/ck_563aca97de12b721e28750b6c60997e3.png)
The circumference of two concentric rings are 88cm and 66cm respectively The width between the rings is : a) - Maths - Perimeter and Area - 14200163 | Meritnation.com
![Consider a ring of radius R with the total charge Q spread uniformly over its perimeter. What is the potential difference between the point at the center of the ring and a Consider a ring of radius R with the total charge Q spread uniformly over its perimeter. What is the potential difference between the point at the center of the ring and a](https://homework.study.com/cimages/multimages/16/imgpsh_fullsize_anim5141257645676270017.jpg)
Consider a ring of radius R with the total charge Q spread uniformly over its perimeter. What is the potential difference between the point at the center of the ring and a
![Set Round with Different Thickness Perimeter Outline, Vector Circle Washer Design Element Circle, Round, Lap Ring Stock Vector - Illustration of design, scribble: 184296018 Set Round with Different Thickness Perimeter Outline, Vector Circle Washer Design Element Circle, Round, Lap Ring Stock Vector - Illustration of design, scribble: 184296018](https://thumbs.dreamstime.com/z/set-round-different-thickness-perimeter-outline-vector-circle-washer-design-element-lap-ring-184296018.jpg)