1. p = a + b + c2 = 12(6 + 7 + 8) = 10.5
S = √p(p - a)(p - b)(p - c) =
= √(10.5)(10.5 - 6)(10.5 - 7)(10.5 - 8) =
= √(10.5)·(4.5)·(3.5)·(2.5) = √413.4375 = 21√154 ≈ 20.33316256758894
2. p = a + b + c2 = 12(3 + 4 + 6) = 6.5
S = √p(p - a)(p - b)(p - c) =
= √(6.5)(6.5 - 3)(6.5 - 4)(6.5 - 6) =
= √(6.5)·(3.5)·(2.5)·(0.5) = √28.4375 = √4554 ≈ 5.332682251925386
3. p = a + b + c2 = 12(12 + 14 + 16) = 21
S = √p(p - a)(p - b)(p - c) =
= √21(21 - 12)(21 - 14)(21 - 16) =
= √21·9·7·5 = √6615 = 21√15 ≈ 81.33265027035576