hi every one, i have one doubt i studied abt trignomentry. there finding the triangle angle or side of the triangle using sine function. if we are taking right angle triangle sine A = opp/hypo, cos A = adj/hypo and tan A=opp/adj. here we are finding angle for A only why we are having three formulas what is the use for that?. and how we are finding sin A. what is the procedure behind that for ex: sin 90 = 1 how this ans come? Pls anybody reply me.