Re: Math/Geometry Guru anyone?
Re: Math/Geometry Guru anyone?
- Subject: Re: Math/Geometry Guru anyone?
- From: Olivier Hamonnière <email@hidden>
- Date: Wed, 06 Dec 2000 01:02:05 +0100
>
> I a drawing pie charts in Ilustrator 9 and need an equation to find the
>
intersecting point of a line extended from the center point the length of
>
the radius.
>
>
Diameter 72 pts
>
Radius 36 pts
>
Center point coordinate 0,0
>
Angle of line extended 45
>
Any ideas on the point coordinates of the intersection of the circle?
If I'm not mistaken, the coordinates of the point you're interested in is:
x = x0 + r * cos (angle)
y = y0 + r * sin (angle)
where x0,y0 are the coordinates of the center of the circle
r the radius of the circle
angle, the angle of the line originating from the centre of the circle
relative to the horizontal
So, in your example:
x = 0 + 36 * cos (pi/4) = 36 * 2^(1/2)/2 = 25 (25.45...)
y = 0 + 36 * sin (pi/4) = 36 * 2^(1/2)/2 = 25 (25.45...)
Remember that the angles are measured counter clockwise, 0 degrees
corresponding to an horizontal line extending from the center to the right.
Hope that helps.
Olivier