Re: Re: [Flashcoders] Area of a triangle using perimiter values only
I recind half of what I said after actually thinking about it, but
maybe it's a different perspective ;)
On 12/14/06, Jordan Snyder [EMAIL PROTECTED] wrote:
To dodge your question, couldn't you just use the simple distance
forumula to determine the base even when it's not horizontal? I dont'
know much about your application or if you'll have the points where
the triangle's points lie, but that's just an idea.
Oh, but I just thought of something from my old rusty brain. I looked
at the formula on the mathworld page; would that not indicate a
distributive method of multiplication? Again, rusty, but a thought.
Let us know what you figure out!!
Cheers
On 12/14/06, Merrill, Jason [EMAIL PROTECTED] wrote:
I'm trying to figure the area of a triangle in Actionscript using the
perimeter values only, not the traditional simple formula:
area = (height/2)*base
because figuring the height is tricky given the triangle will be drawn
in odd ways (i.e. a not horizontally alinged base), so I am exploring
other triangle area forumulas that only take in the perimiter values
(a,b,c), like Heron's formula or this one, which I like:
given a,b,c are the length of the sides of the triangle, then the
formula is:
squareRoot of: (a+b+c)(b+c-a)(c+a-b)(a+b-c)
___
4
So in trying to translate that to actionscript, I wrote:
public static function areaOfTriangle(a:Number, b:Number,
c:Number):Number{
return (Math.sqrt((a+b+c)*(b+c-a)*(c+a-b)*(a+b-c)))/4;
}
But the problem is (a+b+c)*(b+c-a)*(c+a-b)*(a+b-c) results in a negative
number, and this the square root cannot be taken. Or perhaps I am
interpreting the forumula incorrectly:
http://mathworld.wolfram.com/TriangleArea.html
What am I doing wrong here? Thanks.
Jason Merrill
Bank of America
Learning Organizational Effectiveness
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Re: Re: Re: [Flashcoders] Area of a triangle using perimiter values only
ALL RIGHT
I'm a silly billy. I used your code and it works just fine. Maybe
the problem isn't in this function.
I'm using Flash 8/AS2.
Cheers
On 12/14/06, Jordan Snyder [EMAIL PROTECTED] wrote:
I recind half of what I said after actually thinking about it, but
maybe it's a different perspective ;)
On 12/14/06, Jordan Snyder [EMAIL PROTECTED] wrote:
To dodge your question, couldn't you just use the simple distance
forumula to determine the base even when it's not horizontal? I dont'
know much about your application or if you'll have the points where
the triangle's points lie, but that's just an idea.
Oh, but I just thought of something from my old rusty brain. I looked
at the formula on the mathworld page; would that not indicate a
distributive method of multiplication? Again, rusty, but a thought.
Let us know what you figure out!!
Cheers
On 12/14/06, Merrill, Jason [EMAIL PROTECTED] wrote:
I'm trying to figure the area of a triangle in Actionscript using the
perimeter values only, not the traditional simple formula:
area = (height/2)*base
because figuring the height is tricky given the triangle will be drawn
in odd ways (i.e. a not horizontally alinged base), so I am exploring
other triangle area forumulas that only take in the perimiter values
(a,b,c), like Heron's formula or this one, which I like:
given a,b,c are the length of the sides of the triangle, then the
formula is:
squareRoot of: (a+b+c)(b+c-a)(c+a-b)(a+b-c)
___
4
So in trying to translate that to actionscript, I wrote:
public static function areaOfTriangle(a:Number, b:Number,
c:Number):Number{
return (Math.sqrt((a+b+c)*(b+c-a)*(c+a-b)*(a+b-c)))/4;
}
But the problem is (a+b+c)*(b+c-a)*(c+a-b)*(a+b-c) results in a negative
number, and this the square root cannot be taken. Or perhaps I am
interpreting the forumula incorrectly:
http://mathworld.wolfram.com/TriangleArea.html
What am I doing wrong here? Thanks.
Jason Merrill
Bank of America
Learning Organizational Effectiveness
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Jordan Snyder
jordansnyder.com
Applications Developer
Image Action LLC
http://www.imageaction.com
--
Jordan Snyder
Applications Developer
Image Action LLC
http://www.imageaction.com
--
Jordan Snyder
Applications Developer
Image Action LLC
http://www.imageaction.com
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RE: Re: [Flashcoders] Area of a triangle using perimiter values only
Without looking up the source of that formula (i.e., just based on what
you wrote), I determine this: that in order for the result of
multiplication to be negative, one of the terms containing subtraction
must be negative. In order for that to occur, one side of your triangle
is longer than the sum of the other two. That is impossible. Check
your parameters.
P.
-Original Message-
From: [EMAIL PROTECTED] [mailto:flashcoders-
[EMAIL PROTECTED] On Behalf Of Jordan Snyder
Sent: Thursday, December 14, 2006 11:36 AM
To: Flashcoders mailing list
Subject: Re: Re: [Flashcoders] Area of a triangle using perimiter
values
only
I recind half of what I said after actually thinking about it, but
maybe it's a different perspective ;)
On 12/14/06, Jordan Snyder [EMAIL PROTECTED] wrote:
To dodge your question, couldn't you just use the simple distance
forumula to determine the base even when it's not horizontal? I
dont'
know much about your application or if you'll have the points where
the triangle's points lie, but that's just an idea.
Oh, but I just thought of something from my old rusty brain. I
looked
at the formula on the mathworld page; would that not indicate a
distributive method of multiplication? Again, rusty, but a
thought.
Let us know what you figure out!!
Cheers
On 12/14/06, Merrill, Jason [EMAIL PROTECTED]
wrote:
I'm trying to figure the area of a triangle in Actionscript using
the
perimeter values only, not the traditional simple formula:
area = (height/2)*base
because figuring the height is tricky given the triangle will be
drawn
in odd ways (i.e. a not horizontally alinged base), so I am
exploring
other triangle area forumulas that only take in the perimiter
values
(a,b,c), like Heron's formula or this one, which I like:
given a,b,c are the length of the sides of the triangle, then the
formula is:
squareRoot of: (a+b+c)(b+c-a)(c+a-b)(a+b-c)
___
4
So in trying to translate that to actionscript, I wrote:
public static function areaOfTriangle(a:Number, b:Number,
c:Number):Number{
return (Math.sqrt((a+b+c)*(b+c-a)*(c+a-b)*(a+b-
c)))/4;
}
But the problem is (a+b+c)*(b+c-a)*(c+a-b)*(a+b-c) results in a
negative
number, and this the square root cannot be taken. Or perhaps I
am
interpreting the forumula incorrectly:
http://mathworld.wolfram.com/TriangleArea.html
What am I doing wrong here? Thanks.
Jason Merrill
Bank of America
Learning Organizational Effectiveness
___
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--
Jordan Snyder
jordansnyder.com
Applications Developer
Image Action LLC
http://www.imageaction.com
--
Jordan Snyder
Applications Developer
Image Action LLC
http://www.imageaction.com
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Re: Re: [Flashcoders] Area of a triangle using perimiter values only
Jason,
It must be true that your inputs are incorrect, BUT to answer your
question about distributive methods - I was just thinking about
condensing that formula. If you did that(and they do it in the next
step on the MathWorld link) then you have to multiply every term in
parens by every other term in parens and you get all of that whacky
a^4, b^4 business. As it is, you're supplying your function with the
values of a, b, and c, so you can add them in the parens and multiply
out the whole numbers. False alarm there!
Cheers
On 12/14/06, Nex Ninek [EMAIL PROTECTED] wrote:
Negative result of ((a+b+c)*(b+c-a)*(c+a-b)*(a+b-c)) is not possible if a,b,
and c are lengths of a triangle's sides. The first term will always be
obviously positive, and so will the other three terms -- they are simply
the sum of the lengths of two sides less the third side, and you can't have
a triangle where that isn't true. It's most likely that your input numbers
to the formula are incorrect. Trace that to find your problem.
On 12/14/06, Merrill, Jason [EMAIL PROTECTED] wrote:
I'm trying to figure the area of a triangle in Actionscript using the
perimeter values only, not the traditional simple formula:
area = (height/2)*base
because figuring the height is tricky given the triangle will be drawn
in odd ways (i.e. a not horizontally alinged base), so I am exploring
other triangle area forumulas that only take in the perimiter values
(a,b,c), like Heron's formula or this one, which I like:
given a,b,c are the length of the sides of the triangle, then the
formula is:
squareRoot of: (a+b+c)(b+c-a)(c+a-b)(a+b-c)
___
4
So in trying to translate that to actionscript, I wrote:
public static function areaOfTriangle(a:Number, b:Number,
c:Number):Number{
return (Math.sqrt((a+b+c)*(b+c-a)*(c+a-b)*(a+b-c)))/4;
}
But the problem is (a+b+c)*(b+c-a)*(c+a-b)*(a+b-c) results in a negative
number, and this the square root cannot be taken. Or perhaps I am
interpreting the forumula incorrectly:
http://mathworld.wolfram.com/TriangleArea.html
What am I doing wrong here? Thanks.
Jason Merrill
Bank of America
Learning Organizational Effectiveness
___
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Image Action LLC
http://www.imageaction.com
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Re: RE: [Flashcoders] Area of a triangle using perimiter values only
)-Math.pow(c,2))/2*a*b);
return angle;
} else if ( (c == undefined) || (c == null) ) {
c =
Math.sqrt(Math.pow(a,2)+Math.pow(b,2)-2*a*b*Math.cos(angleC));
return c;
}
}
//
/***
**
*
* Method : angleRule
*
* Refers to the angle rule
* angleC + angleA + angleB = 180
*
* @param : angleA - the angle opposed to the a side
*angleB - the angle opposed to the b
side
*
*/
//
public static function angleRule(angleA:Number,
angleB:Number):Number {
var angleC:Number;
angleC = 180 - (angleA + angleB);
return angleC;
}
//
/***
**
*
* Method : area
*
* Calculates the area of a triangle (best for a rectangle
triangle)
* A = b*h/2
*
* @param : b - the base of the triangle
*h - the height of the triangle
*
*/
//
public static function area(b:Number, h:Number):Number {
var area:Number;
area = b*h/2;
return area;
}
//
/***
**
*
* Method : areaHeron
*
* Calculates the area of a triangle where s is the triangle's
semiperimeter
* s = a+b+c/2
* A = sqrt(s(s-a)(s-b)(s-c))
*
* @param : a - the a side
*b - the b side
*c - the c side
*
*/
//
public static function areaHeron(a:Number, b:Number,
c:Number):Number {
var area:Number;
area = Math.sqrt((a+b+c)*(a+b-c)*(b+c-a)*(c+a-c))/4;
return area;
}
}
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Merrill,
Jason
Sent: 14 décembre 2006 14:06
To: Flashcoders mailing list
Subject: RE: [Flashcoders] Area of a triangle using perimiter values only
Thanks - all, yes Jake saw it first and others chimed in with the same
thought, my numbers did not compute because they did not make a triangle. I
have it working now.
The formula is fine, and this function works for me as long as the values
come from a true triangle:
public static function areaOfTriangle(a:Number, b:Number,
c:Number):Number{
return (Math.sqrt((a+b+c)*(b+c-a)*(c+a-b)*(a+b-c)))/4;
}
Thanks eveyrone!
Jason Merrill
Bank of America
Learning Organizational Effectiveness
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