Vài giây trước

Đáy BC dài số cm là

$200\times2:25=16\left(cm\right)$

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Vài giây trước

Áp dụng hệ thức lượng:

@$\dfrac{1}{AH^2}=\dfrac{1}{AB^2}+\dfrac{1}{AC^2}$

$\Leftrightarrow\dfrac{1}{24^2}=\dfrac{1}{30^2}+\dfrac{1}{AC^2}$

$\Leftrightarrow\dfrac{1}{AC^2}=\dfrac{1}{1600}$

$\Leftrightarrow AC=40\left(cm\right)$

@Áp dụng định lý pytago $BC=\sqrt{30^2+40^2}=\sqrt{2500}=50\left(cm\right)$

@$AB^2=BH.BC$

$\Rightarrow BH=\dfrac{30^2}{50}=18\left(cm\right)$

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Vài giây trước

pytago$\Rightarrow BH=\sqrt{AB^2-AH^2}=\sqrt{30^2-24^2}=18cm$

$có:AB^2=BH.BC\Leftrightarrow BC=\dfrac{AB^2}{BH}=50cm$

$pytago\Rightarrow AC=\sqrt{BC^2-AB^2}=\sqrt{50^2-30^2}=40cm$

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Does Victoria often skate in the park? - No, she doesn't
Does Chris sometimes play computer games? - No, he doesn't
Does Victoria usually stay at home? - No, she doesn't
Does Peter always watch TV? - No, he doesn't
Does Sylvia often go out with friends? - No, she doesn't

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