SOLUTION: Help me figure this out, In a triangle, two sides that measure 6 cm and 10 cm form an angle that measures 80 degrees. Find, to the nearest degree, the measure of the smallest ang

Algebra ->  Triangles -> SOLUTION: Help me figure this out, In a triangle, two sides that measure 6 cm and 10 cm form an angle that measures 80 degrees. Find, to the nearest degree, the measure of the smallest ang      Log On


   



Question 790000: Help me figure this out,
In a triangle, two sides that measure 6 cm and 10 cm form an angle that measures 80 degrees. Find, to the nearest degree, the measure of the smallest angle in the triangle.

Answer by rothauserc(4718) About Me  (Show Source):
You can put this solution on YOUR website!
use the law of cosines to find the length of the third side
c^2 = 10^2 + 6^2 - 2*10*6(cos(80))
c^2 = 136 -120*.17
c^2 = 136 -20.84
c = 10.7
now use the law of sines
a/sin(A) = b/sin(B) = c / sin(C)
10.7 / sin(80) = 10 / sin(B) = 6 / sin(C)
sin(B) = 10 / 10.7 = .934
sin(69) = .934
now
80 + 69 = 149 and
180 - 149 = 31
therefore the smallest angle is 31 degrees