Решение:
Сторона:
c = √a2 + b2 - 2ab·cos(γ°)
= √52 + 162 - 2·5·16·cos(120°)
= √25 + 256 - 160·-0.5
= √361
= 19
Угол:
α° = arcsin(
sin(γ°))
= arcsin(
sin(120°))
= arcsin(0.2632·0.866)
= 13.18°
или:
α° = arccos(
)
= arccos(
)
= arccos(
)
= 13.17°
Угол:
β° = arcsin(
sin(γ°))
= arcsin(
sin(120°))
= arcsin(0.8421·0.866)
= 46.82°
Периметр:
P = a + b + c
= 5 + 16 + 19
= 40
Площадь:
p =
S =√p·(p-a)·(p-b)·(p-c)
=√20·(20-5)·(20-16)·(20-19)
=√20 · 15 · 4 · 1
=√1200
= 34.64
Высота :
ha =
=
= 13.86
hb =
=
= 4.33
hc =
=
= 3.646