Answer:
57 degree
Step-by-step explanation:
Using cos formula again~
So AB^2=BC^2+AC^2-2*BC*AC*cosC
AB= 25.15cm
BC^2=AB^2+AC^2-2ABACcosA
Cos A=0.55
A=56.58degree
$337.05
450 x (1- 0.3)= $315
$315 x (1+0.07)= $337.05