Answer:
0.9
Step-by-step explanation:
Basic angle =
[tex]cos { }^{ - 1} ( \frac{4}{5} ) = 36.870 \: degrees \\ [/tex]
Therefore,
[tex]theta = 180 + 36.870 = 216.87 \: degrees[/tex]
Therefore,
[tex] \sin( \frac{theta}{2} ) = \sin(108.435 ) = 0.9[/tex]
