SOLUTION: Three numbers A, B, C are in ratio a: b: c, if the following proportion is true: A/a=B/b=C/c. If the angles of a triangle are in ratio 3: 4: 5, find the ratio of the corresponding

Algebra ->  Trigonometry-basics -> SOLUTION: Three numbers A, B, C are in ratio a: b: c, if the following proportion is true: A/a=B/b=C/c. If the angles of a triangle are in ratio 3: 4: 5, find the ratio of the corresponding      Log On


   



Question 1198385: Three numbers A, B, C are in ratio a: b: c, if the following proportion is true:
A/a=B/b=C/c. If the angles of a triangle are in ratio 3: 4: 5, find the ratio of the corresponding sides

Answer by ikleyn(52798) About Me  (Show Source):
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Three numbers A, B, C are in ratio a: b: c, if the following proportion is true:
A/a=B/b=C/c. If the angles of a triangle are in ratio 3: 4: 5,
find the ratio of the corresponding sides
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If the angles of the triangle are in ratio A:B:C = 3:4:5, it means that
A = 3x, B = 4x, C = 5x,  where x is the common measure.


Then 3x + 4x + 5x = = 180°,  or  12x = 180°,  which implies  x = 180°/12 = 15°.


Hence, A = 45°,  B = 60°,  C = 75°.


Due to the sine law, it implies

    a%2Fsin%2845%5Eo%29 = b%2Fsin%2860%5Eo%29 = c%2Fsin%2875%5Eo%29.


Thus the ratio of the corresponding sides is  

    a:b:c = sin(45°) : sin(60°) : sin(75°) = sqrt%282%29%2F2 : sqrt%283%29%2F2 : %28sqrt%286%29+%2B+sqrt%282%29%29%2F4 = 

                                           = sqrt%282%29 : sqrt%283%29 : %28sqrt%286%29%2Bsqrt%282%29%29%2F2 = 1.414 : 1.732 : 1.932 (rounded).   ANSWER

Solved.