SOLUTION: in triangle ABC, A=47 degrees,b=12,c=8.find a to the nearest tenth a)6.3 b)8.7 c)8.8 d)18.4

Algebra ->  Trigonometry-basics -> SOLUTION: in triangle ABC, A=47 degrees,b=12,c=8.find a to the nearest tenth a)6.3 b)8.7 c)8.8 d)18.4      Log On


   

Question 211794: in triangle ABC, A=47 degrees,b=12,c=8.find a to the nearest tenth
a)6.3
b)8.7
c)8.8
d)18.4
Answer by HyperBrain(694) About Me  (Show Source):
You can put this solution on YOUR website!
Draw CE such that CE is perpendicular to line AB.
Triangle AEC is a right triangle.
Let h=CE
h=b sin A =12 sin 47 = 8.776
AE=sqrt%28b%5E2+-+h%5E2%29=sqrt%2812%5E2+-+8.776%5E2%29=+sqrt%2866.982%29=8.184
Let d=BE
BE=AE-Be=8.184-8=0.184
+a=+sqrt%28BE%5E2+%2B+h%5E2%29=sqrt%280.184%5E2+%2B+8.776%5E2%29=sqrt%2877.052%29=8.778+
So, a=8.778