RosettaCodeData/Task/Arithmetic-geometric-mean/Quite-BASIC/arithmetic-geometric-mean.basic

10 LET A = 1
20 LET G = 1 / SQR(2)
30 GOSUB 100
40 PRINT A
50 END
100 LET T = A
110 LET A = (A + G) / 2
120 LET G = SQR(T * G)
130 IF A < T THEN 100
140 RETURN