SSS Triangle Solver
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Never work on an SSS triangle again!

I've created a program to solve any triangle given its three sides.
Using the law of cosines and the law of sines, this program will output the angles of any triangle.


Code:

"The SSS
"Triangle Solver!
"Made By
"Erica DiGiulio
//Get variables
Input "Side a=",A
Input "Side b=",B
Input "Side c=",C
//Testing if the triangle is valid
If A+B<=C or A+C<=B or B+C<=A or A<=0 or B<=0 or C<=0
Then
Disp " "
Disp "Not a valid"
Disp "Triangle"
Stop
End
//Testing for equilateral triangles
If A=B and B=C
Then
Disp " "
Disp "All angles are"
Disp "60^^o"
Stop
End
//Testing for isosceles trianges
If A=B or A=C or B=C
Then
Goto 3
Else
Goto 4
End
//Isosceles solver
Lbl 3
If A=B
Then
cos^-1(((C/2)/A)->H
H->G
180-(H+G)->I
End

If A=C
Then
cos^-1(((B/2)/A)->I
I->G
180-(I+G)->H
End

If C=B
Then
cos^-1(((A/2)/C)->H
H->G
180-(H+I)->G
End

Goto 42
//Testing for longest side
Lbl 4
If A>B and A>C
Then
Goto 6
Else
Goto 5
End

Lbl 5
If B>C and B>A
Then
Goto 7
Else
Goto 8
End
//Calculating angles
//Variables will be saved ABC->GHI and then will be converted back
Lbl 6
cos^-1(((B^^2+C^^2-A^^2)/(2BC))->G
sin^-1(((B/A)*(sin(G))->H
180-(G+H)->I
Goto 42

Lbl 7
cos^-1(((A^^2+C^^2-B^^2)/(2AC))->H
sin^-1(((A/B)*(sin(H))->G
180-(G+H)->I
Goto 42

Lbl 8
cos^-1(((A^^2+B^^2-C^^2)/(2AB))->I
sin^-1(((A/C)*(sin(I))->G
180-(I+G)->H
Goto 42
//Display the answer
Lbl 42
round(G,2)->A
round(H,2)->B
round(I,2)->C
Disp " "
ClrHome
Output(2,2,"Angle A: ")
Output(2,11,A)
Output(3,2,"Angle B: ")
Output(3,11,B)
Output(4,2,"Angle C: ")
Output(4,11,C)
Disp " "
Disp " "
Disp " "
Disp " "
Disp " "
Stop
May I suggest, from looking at your code,using an Output( comand?

My Stuff
Unicorn wrote:
May I suggest, from looking at your code,using an Output( comand?


I'm using output for the last parts because it won't fit otherwise, but I don't think the other ones really need it.
why not using the simple cosine rule:
a^2=b^2+c^2-2bc cos(alpha)
?

I created a simple new program, without comments etc. but even faster Smile
First my code checks whether the triangle is possible, Triangle Inequality Theorem. Then it calculates two angles using the cosine rule, the third angle is 180-A-B
Here it is:

Code:

Degree
Input "Side a=",A
Input "Side b=",B
Input "Side c=",C
If A+B>C and A+C>B and B+C>A
Then
cos^-1(.5B^^-1C^^-1(B^^2+C^^2-A^^2->G
cos^-1(.5A^^-1C^^-1(A^^2+C^^2-B^^2->H
180-G-H->I
round(G,2->A
round(H,2->B
round(I,2->C
ClrHome
Output(2,2,"Angle A:
Output(2,11,A
Output(3,2,"Angle B:
Output(3,11,B
Output(4,2,"Angle C:
Output(4,11,C
Return
Else
Disp " ","Not a valid","Triangle
Return
End
PT_ wrote:
why not using the simple cosine rule:
a^2=b^2+c^2-2bc cos(alpha)
?

I created a simple new program, without comments etc. but even faster Smile
First my code checks whether the triangle is possible, Triangle Inequality Theorem. Then it calculates two angles using the cosine rule, the third angle is 180-A-B
Here it is:

Code:

Degree
Input "Side a=",A
Input "Side b=",B
Input "Side c=",C
If A+B>C and A+C>B and B+C>A
Then
cos^-1(.5B^^-1C^^-1(B^^2+C^^2-A^^2->G
cos^-1(.5A^^-1C^^-1(A^^2+C^^2-B^^2->H
180-G-H->I
round(G,2->A
round(H,2->B
round(I,2->C
ClrHome
Output(2,2,"Angle A:
Output(2,11,A
Output(3,2,"Angle B:
Output(3,11,B
Output(4,2,"Angle C:
Output(4,11,C
Return
Else
Disp " ","Not a valid","Triangle
Return
End


That's pretty much what I did, but in a different order. Also, don't you have to apply this rule to the longest side? I thought that was necessary.
  
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