please help me. i dont know how to do it.

Answer:
[tex]A = 48.815[/tex]
Step-by-step explanation:
[tex] \frac{a}{ \sin(A) } = \frac{b}{ \sin(B) } [/tex]
[tex] \frac{12.5}{ \sin(A) } = \frac{15.4}{ \sin(68) } [/tex]
[tex]12.5 \sin(68) = 15.4 \sin(A) [/tex]
[tex] \frac{12.5 \sin(68) }{15.4} = \frac{15.4 \sin(A) }{15.4} [/tex]
[tex] \sin(A) = \frac{12.5 \sin(68) }{15.4} [/tex]
[tex] A=\sin ^{ - 1} ( \frac{12.5 \sin(68) }{15.4} ) [/tex]
[tex]A = 48.815[/tex]