Respuesta :

[tex]BC^2=AB^2+AC^2-2*AB*AC*cos(54^o) \\ \\BC^2=15.8^2+7.4^2-2*15.8*7.4* 0.5878 = \\ =249.64 + 54.76 -137.45 = 166.95 \\ \\ BC= \sqrt{166.95}\approx 12.92 \ units[/tex]
irspow
a^2=b^2+c^2-2bccosA

a^2=7.4^2+15.8^2-2(7.4)(15.8)cos54°

a^2=304.4-233.84cos54°

a=√(304.4-233.84cos54°) units

a≈12.92 units (to the nearest hundredth of a unit)