Решение:
Сторона:
b = √a2 + c2 - 2ac·cos(β°)
= √1002 + 1002 - 2·100·100·cos(80°)
= √10000 + 10000 - 20000·0.1736
= √16528
= 128.56
Высота :
ha =
=
= 320
hc =
=
= 320
Угол:
α° = arcsin(
sin(β°))
= arcsin(
sin(80°))
= arcsin(0.7778·0.9848)
= 49.99°
или:
α° = arccos(
)
= arccos(
128.562+1002-1002
2·128.56·100
)
= arccos(
16527.6736+10000-10000
25712
)
= 50°
Угол:
γ° = arcsin(
sin(α°))
= arcsin(
sin(80°))
= arcsin(0.7778·0.9848)
= 49.99°
Периметр:
P = a + b + c
= 100 + 128.56 + 100
= 328.56
hb =
=
= 248.91