100 REM PIE
110 READ D
120 DATA 10
130 LET S = 1
140 LET N = 6
150 FOR I = 1 TO D
160     LET X = S/2
170     LET Y = 1 - SQR(1 - X*X)
180     LET S = SQR(X*X + Y*Y)
190     LET N = 2*N
200     LET P = N*S/2
210     PRINT I, P
220 NEXT I
230 END
