Question

Can someone please help me with this!?

Answer 1

Answer:

Applying cosine theorem:

AB = sqrt(AC^2 + BC^2 - 2 x AB x BC x cosC)

     = sqrt( 72^2 + 135^2 - 2 x 72 x 135 x cos(119deg))

     = 181

Applying sine theorem:

BC/sinA = AB/sinC

=> sinA = BC x sinC/AB

=> A = arcsin(BC x sinC/AB)

        = arcsin( 135 x sin(119deg)/181)

        = 40.7 deg

Hope this helps!

:)