Respuesta :

The answer is approximately -457.9F
hello : 
115°+X° = 180°
X° = 180° - 115°
X° = 65°
but : 65° +(4k+5)° +(6k+10)° = 180°.. ( sum angles in the triangle)
10K +80° =180°
10K =100°
k = 10°