
Thanks Hartmut for the HP15C test. It seems HP15C does *decimal* math, 10 significant digits, halfroundup s = (a + b + c) / 2 = (1e5 + 99999.99979 + 0.00029) / 2 = (199999.9998 + 0.00029) / 2  round up = 200000.0001 / 2  round up again = 100000.0001  halfroundup I have never seen a calculator like this ... With this, I match your area result of 17.60681685 exactly. On Tue, 12 Jun 2018, Albert Chan wrote:BTW, the article stated that heron formula return area = 17.6I cannot reproduce it (even adjusting precision with gmpy2)Anyone still have the old HP15C calculator ?
