Answer:
A= 41° a=9.84... b=11.32...
Explanation:
given B = 49° and C = 90°
and A + B + C = 180
so 49+90+A=180
A= 41°
we also know c (small) is 15 units
and maybe you know this SOH CAH TOA? no, i'm not calling anyone names :P this is just the mnemonic to memorize how sin , cos and tan fit sin(Ф)=Opp/Hyp Cos(Ф)=Adj/Hyp Tan(Ф)=Opp/Adj
Hyp is the hypontenuse of the triangle ( the long side). Opposite (Opp) means the side opposite from what ever angle you are starting at..adjacent (Adj) means what ever angle is next to where you are starting from.
use Cos(49) to find the side a
a is an adjacent side to the 49 angle. We know the Cos and we know the Hyp .. so solve for adj...
Cos(Ф)=Adj/ Hyp
Hyp*Cos(Ф)=Adj
15*Cos(49)= Adj
9.84...=Adj=a
now lets' use sin for the opposite side or b
sin(Ф)=Opp/Hyp
Hyp*Sin(Ф) = Opp
15*sin(49)= Opp
11.32...= Opp =b