Two angles are called complementary if their measures add to 90 degrees, and called supplementary if their measures add to 180 degrees.
In radians this are
[tex]\begin{gathered} \frac{\pi}{2}\text{ for }90\degree \\ \pi\text{ for }180\degree \end{gathered}[/tex]To find the complement of 3π/4, subtract it by π/2
[tex]\frac{\pi}{2}-\frac{3\pi}{4}=-\frac{\pi}{4}[/tex]To find the supplement of 3π/4, subtract it by π.
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