How do you solve the triangle given A=30, a=14, b=28?

1 Answer
Apr 25, 2018

It's yet another 30,60,90 triangle so B=90^circB=90, C=60^circC=60 and c=14 sqrt{3}c=143.

Explanation:

Oh my gosh, another trig problem with 30^circ30. Why have we created an entire field that handles only two triangles?

The Law of Sines says

a/sinA = b /sin B = c / sin CasinA=bsinB=csinC

sin B = b/a sin A = 28/14 sin 30^circ = 2 (1/2) = 1 sinB=basinA=2814sin30=2(12)=1

Interestingly, 11 is the only sine that uniquely determines a triangle angle because it's its own supplement.

B = 90^ circ B=90

It's another 30,60,90 triangle and I just want to crawl in a hole. Get a new triangle, question writers!

C=180^circ -A - B = 180^circ - 30^circ - 90^circ = 60^circC=180AB=1803090=60

c = a \ sin C/sin A = {(14) (sqrt{3}/2)} / (1/2) = 14 sqrt{3} c=a sinCsinA=(14)(32)12=143