Решение:
Сторона:
b = √a2 + c2 - 2ac·cos(β°)
= √42 + 3.452 - 2·4·3.45·cos(55°)
= √16 + 11.9 - 27.6·0.5736
= √12.07
= 3.474
Высота :
hc = a·sin(β°)
= 4·sin(55°)
= 4·0.8192
= 3.277
Угол:
α° = arcsin(
sin(β°))
= arcsin(
sin(55°))
= arcsin(1.151·0.8192)
= 70.54°
или:
α° = arccos(
)
= arccos(
3.4742+3.452-42
2·3.474·3.45
)
= arccos(
12.068676+11.9025-16
23.97
)
= 70.58°
Угол:
γ° = arcsin(
sin(α°))
= arcsin(
sin(55°))
= arcsin(0.9931·0.8192)
= 54.44°
Периметр:
P = a + b + c
= 4 + 3.474 + 3.45
= 10.92
Площадь:
p =
S =√p·(p-a)·(p-b)·(p-c)
=√5.462·(5.462-4)·(5.462-3.474)·(5.462-3.45)
=√5.462 · 1.462 · 1.988 · 2.012
=√31.940626096064
= 5.652
Высота :
ha =
=
= 2.826
hb =
=
= 3.254