Question

геометрия

помогите пожалуйста!

Answer 1

1)Дано: AB=5см, <B=45градусов, <C=60градусов
Найти: <A,BC,AC.
Решение:
<A=180градусов-(<B+<C)=180градусов-105градусов=75градусов
по теореме синусов 5/sin60град=BC/sin75град, BC=5*0,9659/0,8660= 5,58м
5/sin60град=AC/sin45град, AC= 5*9659/0,8660=4,08м

2)BC=4,125м; <b=44град, <C=72град
<A=180-72-44=64град
по теореме синусов:
AB/sin72=4,125/sin64, AB= 4,125*0,9511/0,8988=4,365м
Sabc=1/2*AB*BC*sin<b
Sabc=1/2*4,125*4,365*sin44=1/2*4,125*4,365*0,6947=6,254м2

3)AB^2=BC^2+AC^2-2*BC*AC*Cos(C)
AB^2=3/16+0.36-2*(3*√3/20)*(-√3/2)=0.1875+0.36+0.45=0.9975
AB=0.9987
AB/Sin(C)=AC/Sin(B)=BC/Sin(A)
0.9987/Sin(150)=0.6/Sin(B)=0.4330/Sin(A)
Sin(B)=0.6*Sin(150)/0.9987=0.3004
B=17.5
C=180-150-17.5=12.5

Answer 2

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