Answer
$c = 163$ inches
Work Step by Step
$c^{2} = a^{2} + b^{2} - 2abcos(\theta)$
$c^{2} = (120)^{2} + (66)^{2} - 2(120)(66)cos(120)$
$c^{2} = 14400 + 4356 - 15840cos(120)$
$c^{2} =18756 - (-7920)$
$c^{2} = 18756 + 7920$
$c^{2} = 26676$
$c = \sqrt {26676}$
$c = 163.32789...$ inches
$c = 163$ inches