you need to use the definitions of sin and cos
[tex]sinx = \frac{opp}{hyp} \\ cosx = \frac{adj}{hyp} [/tex]from the question adj=7 ,hyp=25
since sin and cos are defined for a right triangle then
[tex] {opp}^{2} + {adj}^{2} = {hyp}^{2} [/tex]
solving for opp so we can find sin
[tex]opp = \sqrt{ {hyp}^{2} - {adj}^{2} } [/tex]
so plugging in the numbers
[tex]opp = \sqrt{ {25}^{2} - {7}^{2} } = \sqrt{625 - 49} = \sqrt{576} = 24[/tex]
therefore
[tex]sin(x) = \frac{opp}{hyp} = \frac{24}{25} [/tex]
