Впрямоугольном треугольнике abc угол с=90*, угол а=30*, ас=10 см, cd-высота, проведенная к стороне ав, de- перпендикуляр, проведенный из точки d к стороне ас. чему равна длина ае?
I was tired. (–)
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His sister was a model. (?)
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Masha read magazine. (?)
They were students. (?)
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Tom lied. (–)
Marina wore skirts. (–)
I was tired. (–)
Kris spoke English. (–)
His sister was a model. (?)
I liked my phone. (–)
Masha read magazine. (?)
They were students. (?)
This shop opened at 9 o’clock. (?)
She was pretty. (?)
Tom lied. (–)
Marina wore skirts. (–)
I was tired. (–)
Kris spoke English. (–)
His sister was a model. (?)
I liked my phone. (–)
Masha read magazine. (?)
They were students. (?)
This shop opened at 9 o’clock. (?)
She was pretty. (?)
Tom lied. (–)
Marina wore skirts. (–)
AB=10/sqrt3/2=20/sqrt3=20sqrt3/3 (по свойству стороны напротив угла 60 градусов).
CB=10sqrt3/3 (по свойству стороны напротив угла в 30 градусов).
CD^2=(10sqrt3/3)^2-(5sqrt3/3)^2=300/9-75/9=25 (по теореме Пифагора)
CD=5 cm
AD^2=AC^2-CD^2=100-25=75 cm (по теореме Пифагора)
AD=sqrt75=5sqrt3
Тогда AE=AD*sqrt3/2=5sqrt3*(sqrt3/2)=15/2=7.5 см
(по свойству стороны напротив угла в 60 градусов).