Drawing a circle

[Hank]

Given the equation of a circle (or some derivative), how can I draw a
circle (1 or more) in an XY chart using Excel 2003?

Thanks!

Hank

 

[Pete_UK]

You can use the fact that x = radius * cos(theta) and y = radius *
sin(theta) can be used to draw a circle, as theta varies from -180 to
+180 degrees. If you prefer to work in degrees, put -180 in A2 and
then in A3:

=A2+12

and copy this down to A32 - this will give you 12 degree increments,
though you could change this and the range to suit. In B2 you can
enter this formula:

=RADIANS(A2)

and copy this down to B32. Enter these formulae:

C2: =SIN(B2)
D2: =COS(B2)

and copy them down to row 32 - this assumes a radius of 1. Then
highlight C232 and click on the chart wizard icon and select X Y
scatter as graph type.

This will give you a reasonable circle. If you want it larger, then
multiply the sin and cos values by a constant, which represents the
radius. If you want to move it from the origin, then add or subtract
another constant to the sin and/or cos values.

Hope this helps.

Pete

 

[MartinW]

Hi Hank,

Alternatively you could add a single point series and set say x=3 and
y=10 (or wherever you want the centre of the circle) and format the
marker to be a dot with foreground color set to black and background
set to no color. You can then set the size from 2 to 72 pts. It looks
pretty dodgy on screen put prints out neatly.

HTH
Martin

 

[Hank]

Thanks, that worked great!

Hank

 

[Pete_UK]

Thanks for the feedback - glad to help.

Pete