Прошу, помогите! Найти площади треугольника со сторонами 6,7,8; 3,4,6; 12,14,16

1. p = a + b + c 2 = 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√15 4 ≈ 20.33316256758894

2. p = a + b + c 2 = 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 = √455 4 ≈ 5.332682251925386

3. p = a + b + c 2 = 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