Answer:
[tex]C)\:\:\frac{\sqrt 2}{ 2 } [/tex]
Step-by-step explanation:
[tex] \sin \bigg( \frac{3\pi}{4} \bigg) \\ \\ = \sin \bigg( \pi - \frac{\pi}{4} \bigg) \\ \\ = \sin \bigg(\frac{\pi}{4} \bigg) \\ \\ = \frac{1}{ \sqrt{2} }\\\\= \frac{\sqrt 2}{ 2 }[/tex]
