Answer
127.3
Work Step by Step
For the law of sines, we know that:
$$\frac{a}{\sin \left(\alpha \right)}=\frac{b}{\sin \left(\beta \right)}=\frac{c}{\sin \left(\gamma \right)}$$
Thus, it follows:
$$ a=\frac{90\sin \left(90^{\circ \:}\right)}{\sin \left(45^{\circ \:}\right)} \\ a=127.3$$
