help pls i dont understand how to do this :')

Answer:
7/8
Step-by-step explanation:
Use the Pythagorean Identity
[tex]( \sin(x) ) {}^{2} + ( \cos(x) ) {}^{2} = 1[/tex]
Plug in
[tex] \frac{ \sqrt{15} }{8} [/tex]
for cos x.
[tex] (\sin(x) ) {}^{2} + ( \frac{ \sqrt{15} }{8} ) {}^{2} = 1[/tex]
[tex]( \sin(x) ) {}^{2} + \frac{15}{64} = 1[/tex]
[tex]( \sin(x) ) {}^{2} = \frac{49}{64} [/tex]
[tex] \sin(x) = \frac{7}{8} [/tex]