Given that:
[tex]\cos \theta=\frac{adjacent}{hypothenus}[/tex]
and we are given that:
[tex]\cos \theta=-\frac{7}{8}[/tex]
we can say that:
adjacent = 7, hypothenus = 8
And we can apply the Pythagorean theorem which is:
[tex]\text{hypothenus}^2=opposite^2+adjacent^2[/tex]
Thus, we have that:
[tex]undefined[/tex]
