Calc the angles?

Math and Physics Programming

Started by Sim February 16, 2002 03:05 AM

2 comments, last by Sim 22 years, 2 months ago

122

Author

February 16, 2002 03:05 AM

Hi! How can I calc the angles in a normal triangle (it hasn''t to be a rectanglar), if I have got the lenght of all three sides? thx

Fruny

1,658

February 16, 2002 03:20 AM

a^2 = b^2 + c^2 - 2.b.c.cos A

from which you get the angle A.

Idem for B,C.

"Debugging is twice as hard as writing the code in the first place. Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it." — Brian W. Kernighan

castor

122

February 16, 2002 03:28 AM

a triangle has 3 points(p1,p2,p3) and
3 edges(e1=p2-p1,e2=p3-p1,e3=p3-p3).
now the edges are vectors.
normalize them! e1.normalize() ...
then e.g. to calc the angle btw. e1 and e2 take the
float dot = dotproduct(e1,e2);
to get the angle in radians -> float angle = acos(dot).
if you want angle in degrees -> angle = (angle * PI) / 180;

hope that helps .