10 PRINT "PARABOLIC INTERPOLATION  RESERVOIR AREA CALCULATION": PRINT
20 DEFINT I:   READ Z0, DZ, A(1), A(2), A(3), A(4)
25 DATA 6320., 10., 348., 692., 1217., 2133.
30 PRINT "Z0, DZ, A(1), A(2), A(3), A(4) ="; Z0; DZ; A(1); A(2); A(3); A(4)
40 READ Z:   DATA 6333.53:   I = (Z - Z0) / DZ + 2: TH = (Z - Z0 - (I - 1) * DZ) / DZ: PRINT "I="; I
50 AREA = A(I) + .5 * TH * (A(I + 1) - A(I - 1)) + .5 * TH * TH * (A(I + 1) + A(I - 1) - 2! * A(I))
60 PRINT "Z="; Z; "   AREA="; AREA