Deriving an angle from three points

[James Hurley]

>
> Message: 24
> Date: Tue, 15 Dec 2009 22:21:47 -0800
> From: Mark Swindell <mdswindell at cruzio.com>
> Subject: Deriving an angle from three points
> To: How to use Revolution <use-revolution at lists.runrev.com>
> Message-ID: <B3725793-6274-4F53-91D2-3154D31F9CDF at cruzio.com>
> Content-Type: text/plain;	charset=us-ascii
>
> 40,116
> 98,186
> 132,118
>
> How would one determine the angle created from three points, such as  
> those above?
>
> Thanks,
> Mark
>

Mark,

Or even easier. Set the Turtle at the apex and get the angle of the  
other two points.


on mouseUp
    startTurtle --Initiates the turtle graphics library
    penup
    setxy 98,186 --The vertex
    put direction(40,116) into A
    put direction(132,118) into B
    put B-A into dA
    put abs(dA) & cr & abs(180 - dA)  into msg box
    choose the browse tool
end mouseUP

(Assuming your middle point is the apex of the angle you want.)

To run this you will need the TG library. Run this in the msg box

go url "http://www.jamesphurley.com/jhurleyFolder/TurtleGraphics.rev"

Jim Hurley