Answer:
The answer to your question is Perimeter = 287.3 in
Explanation:
AB = 90 in
BC = 80 in
∠B = 50
Perimeter = ?
Process
1.- We need to find AC using Law of sines

 

 

 A = 42.9 ≈ 43
The sum of the internal angles in a triangle equals 180°
 A + B + C = 180°
 43 + B + 50 = 180
 B = 180 - 43 - 50
 B = 87°


 AC = 117.3 
2.- Find the perimeter
 Perimeter = AB + BC + AC
 Perimeter = 90 + 80 + 117.3
 Perimeter = 287.3 in