Answer
$a \approx 621$ inches
$B = 47.8˚$
$b \approx 491$ inches
Work Step by Step
1. Solve for the missing length $a$
$\frac{a}{sin(110.4)} = \frac{246}{sin(21.8)}$
$a = \frac{246sin(110.4)}{sin(21.8)}$
by GDC / calculator
$a = \frac{230.57...}{0.3713...}$
$a = 620.870...$ inches
$a \approx 621$ inches
2. Solve for the missing angle $B$
$B + 110.4 + 21.8 = 180$
$B + 132.2 = 180$
$B = 47.8˚$
3. Solve for the missing length $b$
$\frac{b}{sin(47.8)} = \frac{246}{sin(21.8)}$
$b = \frac{246sin(47.8)}{sin(21.8)}$
by GDC / calculator
$b = \frac{182.23......}{0.3713...}$
$b = 490.720...$ inches
$b \approx 491$ inches