Enter one side and second value and press the Calculate button:
Expression with sin(angle deg|rad)/cos(angle deg|rad)/tan(angle deg|rad)/asin()/acos()/atan():
sin A = opposite / hypotenuse = a / c
cos A = adjacent / hypotenuse = b / c
tan A = opposite / adjacent = a / b
csc A = hypotenuse / opposite = c / a
sec A = hypotenuse / adjacent = c / b
cot A = adjacent / opposite = b / a