Is it trigo-algebra?
Algebra
Level
3
In a triangle ABC , if , Sin A : Sin B : Sin C :: 6 : 5 : 4
and if , Cos A : Cos B : Cos C :: p : q: r where p, q, and r are co-prime positive integers,
then find the value of pqr - (p + q + r).
The answer is 193.
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1 solution
Hints: i. Sines are proportional to the sides. ii. Cos A = (b^2 + c^2 - a^2)/ 2bc