Предмет: Геометрия, автор: fortnite2090qwerty

помогите решить 7 (теорема Пифагора)​

Приложения:
Аноним: cos30°=BD/AB; √3/2=10/x; x=10*2/√3=20√3/3

Ответы

Автор ответа: 85258
0

Ответ:

x = \frac{40 \sqrt{3} }{3}

Объяснение:

x²=AD²+DB²

напротив угла в 30° лежит половина гипотенузы, следовательно

AD=x/2

отсюда

x²=(x/2)²+DB²

x²-x²/4=DB²

3/4x²=DB²

x²=4/3*DB²

x=√(4/3*10²)

x=40/√3

x=40√3/3

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