Formulas & Data:
- Electronics
- Mathematics
- Physics
- RF & Microwaves

Parts Vendors:
- all hand-selected

- Amateur Radio
- Vintage Articles:
- Electronics World
- Popular Electronics
- QST
- Radio & TV News
- Radio Craft
- Short Wave Craft
- Wireless World

- Events Calendar
RF Cafe Homepage
Copyright 1999-2015   •−•  ••−•    −•−•  •−  ••−•  •   "RF Cafe" in Morse Code  >> Listen to It <<
- EW & Radar Handbook
- Quizzes       - Software
- App Notes
- Calculators
- Advertise on RF Cafe
- About RF Cafe™
- RF Cafe Shirts & Mugs
- RF Cafe Archives
RF Cafe Book Contest
- RF Cafe on Visit RF Cafe on Facebook Visit RF Cafe on Twitter Visit RF Cafe on LinkedIn
- Tech Humor
- Forums Archive
- Job Board
- Donate to RF Cafe
- Kirt's Cogitations
Custom Search
More than 10,000 searchable pages indexed.
Greetings: There is so much good stuff on RF Cafe that there is no way to list or link to all of it here. Please use the Search box or the Site Map to find what you want - there is a good chance I have it here. Thanks!

Geometry - Arcs & Circles

Here are formulas for some of the most commonly used arcs and circles. Equations for area and circumference are provided.








  K = area
  R = radius
  D = diameter
  C = circumference
  θ = central angle (radians)



Circumference of a Circle - RF CafeCircumference and Area





 

Circumference of an Ellipse - RF CafeEllipse

(approx)

Circumference of an Annulus - RF CafeSector of an Annulus

 

   
   
Sector and Segment - RF CafeSector and Segment






 



                   
Parabolic Segment - RF CafeParabolic Segment

K (right segment)


3D Parabolic Segment - RF CafeK (oblique segment) , where T is the area of the triangle
with the base along the chord of the segment and with
opposite vertex at the point on the parabola at which the
tangent to the parabola is parallel to the chord of the segment.


Source: CRC Standard Math Tables, 1987

Your RF Cafe
Progenitor & Webmaster

Click here to read about RF CafeKirt Blattenberger… single-handedly redefining what an engineering website should be.

View the YouTube RF Cafe Intro Video Carpe Diem!
(Seize the Day!)

5th MOB: My USAF radar shop

Airplanes and Rockets: My personal hobby website

Equine Kingdom: My daughter Sally's horse riding website