Решение:
Сторона:
c = √a2 + b2 - 2ab·cos(γ°)
= √1902 + 1002 - 2·190·100·cos(120°)
= √36100 + 10000 - 38000·-0.5
= √65100
= 255.15
Угол:
α° = arcsin(
sin(γ°))
= arcsin(
sin(120°))
= arcsin(0.7447·0.866)
= 40.16°
или:
α° = arccos(
)
= arccos(
1002+255.152-1902
2·100·255.15
)
= arccos(
10000+65101.5225-36100
51030
)
= 40.16°
Угол:
β° = arcsin(
sin(γ°))
= arcsin(
sin(120°))
= arcsin(0.3919·0.866)
= 19.84°
Периметр:
P = a + b + c
= 190 + 100 + 255.15
= 545.15
Площадь:
p =
S =√p·(p-a)·(p-b)·(p-c)
=√272.58·(272.58-190)·(272.58-100)·(272.58-255.15)
=√272.58 · 82.58 · 172.58 · 17.43
=√67710608.621354
= 8228.6
Высота :
ha =
=
= 86.62
hb =
=
= 164.57
hc =
=
= 64.5