Ответ:
1)<β=90-60=30°;b=c/2; c²=9+c²/4; 4c²=36+c²;
4c²-c²=36; 3c²=36; c²=12; c=√12=2√3
b=2√3:2=√3
Sin30° =1/2; Cos30°=√(1-1/4)=√3/4= √3/2;
Tg30° =Sin30°/Cos30°=1/2:√3/2=1/2•2/√3=1/√3=√3/3
2)S=(3+9)/2•h (т.к.<45°, то h=(9-3)2=6:2=3
S=(3+9)•3/2=12•3/2=18
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Ответ:
1)<β=90-60=30°;b=c/2; c²=9+c²/4; 4c²=36+c²;
4c²-c²=36; 3c²=36; c²=12; c=√12=2√3
b=2√3:2=√3
Sin30° =1/2; Cos30°=√(1-1/4)=√3/4= √3/2;
Tg30° =Sin30°/Cos30°=1/2:√3/2=1/2•2/√3=1/√3=√3/3
2)S=(3+9)/2•h (т.к.<45°, то h=(9-3)2=6:2=3
S=(3+9)•3/2=12•3/2=18