| ALPHA : Trigonometry : Triangles 03 : Triangle Cosine Rule : ALPHA Maths Homework Exercise
Description : Triangle cosine rule.
Discussion : The cosine rule can be used to calculate one of the triangle angles if all three sides are known. See figure Triangle Dimensions And Angles
The homework exercise has 2 questions.
side a
angle A
The equations are :
a2 = b2 + c2 - 2 b c cosd(A)
a = √(b2 + c2 - 2 b c cosd(A))
A = acosd((b2 + c2 - a2) / (2 b c))
where
a b c = sides of triangle
A B C = opposite angles of triangle
Note : Angles are in degrees. Use the degree trig functions cosd() and acosd().
Back To Top
|