hello all i need to get the tangent of a circle command into a programe as follows tan (angle of degree/2)

trying just 90degrees /2 =45degrees tan(45) in intermediate window i get 1.619 which is radians , to convert to degrees its 180/pi (3.142) but this gives result of 92.806. rather than 1

if using windows calculator tan 45 =1 which is correct, but have tried all ways to try and get tan command to give the same result , so how can this be done.

thank you