## Elementary Geometry for College Students (6th Edition)

x$\approx$ 10.5
using theorem 11.4.3 Law of cosine $x^{2}$ = $(8)^{2}$ + $(12)^{2}$ - 2*8*12*cos 60° $x^{2}$ = 64+144 - 2*8*12 * $\frac{1}{2}$ $x^{2}$ = 208 -96 $x^{2}$ = 112 x = $\sqrt 112$ x = 4$\sqrt 7$ $\approx$ 10.5 x$\approx$ 10.5