Given:
[tex]\begin{gathered} a=3mi \\ \alpha=45\degree \end{gathered}[/tex]Required:
To find the value of beta, b and c.
Explanation:
The given triangle is right triangle.
Therefore,
[tex]\begin{gathered} \sin\alpha=\frac{a}{c} \\ \\ \sin45=\frac{3}{c} \\ \\ 0.7071=\frac{3}{c} \\ \\ c=\frac{3}{0.7071} \\ \\ c=4.2426mi \end{gathered}[/tex]Now
[tex]\begin{gathered} \tan\alpha=\frac{a}{b} \\ \\ \tan45=\frac{3}{b} \\ \\ 1=\frac{3}{b} \\ \\ b=3 \end{gathered}[/tex]The sum of the angle in triangle is 180 degree.
Therefore
[tex]\begin{gathered} 90+45+\beta=180 \\ \beta=180-90-45 \\ \beta=45\degree \end{gathered}[/tex]Final Answer:
[tex]\begin{gathered} b=3mi \\ c=4.2426mi \\ \beta=45\degree \end{gathered}[/tex]