how do i calculate sin x=25/30

with this calc put the first one enter it likie this

asin(25/30)

and this will be the output :)

$$\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{sin}}^{\!\!\mathtt{-1}}{\left({\frac{{\mathtt{25}}}{{\mathtt{30}}}}\right)} = {\mathtt{56.442\: \!690\: \!238\: \!079^{\circ}}}$$

You can plug the given value into the inverse sin/cos/tan equation (sometimes denoted as sin^-1 or arcsin.) This function will tell you what the measure of the angle is with a given sin/cos/tan