Finding $\dfrac{AC}{BD}$ of a Trapezoid $ABCD$

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In summary, to find the value of AC/BD in a trapezoid, you need to divide the length of one diagonal by the length of the other diagonal. This can be calculated using the formula AC/BD = AC/BD and knowing the lengths of both diagonals. The value can be greater than 1, indicating a more elongated trapezoid, or less than 1, indicating a wider trapezoid. It is not possible for AC/BD to be negative in a trapezoid.
  • #1
Albert1
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A trapezoid $ABCD$ , $BC//AD ,\,\, \angle A=90^o$ , $AC\perp BD$

given :$\dfrac {BC}{AD}=k$

find :$ \dfrac {AC}{BD}$
 
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  • #2
Albert said:
A trapezoid $ABCD$ , $BC//AD ,\,\, \angle A=90^o$ , $AC\perp BD$

given :$\dfrac {BC}{AD}=k$

find :$ \dfrac {AC}{BD}$

Hello.

[tex]If \ \angle{A}=90º \ and \ \overline{BC} // \overline{AD} \rightarrow{}\angle{B}=90º[/tex]

[tex]If \ \overline{BC} // \overline{AD} \rightarrow{}\angle{ADB}=\angle{DBC}= \alpha[/tex]

[tex]\sin{\alpha}=\dfrac{\overline{AB}}{\overline{BD}}=\dfrac{\overline{BC}}{\overline{AC}}[/tex]

[tex]\cos{\alpha}=\dfrac{\overline{AB}}{\overline{AC}}=\dfrac{\overline{AD}}{\overline{BD}}[/tex]

Therefore:

[tex]\overline{AB}=\dfrac{\overline{BC} \ \overline{BD}}{\overline{AC}}[/tex]

[tex]\overline{AB}=\dfrac{\overline{AD} \ \overline{AC}}{\overline{BD}}[/tex]

[tex]\dfrac{\overline{BC} \ \overline{BD}}{\overline{AC}}=\dfrac{\overline{AD} \ \overline{AC}}{\overline{BD}}[/tex][tex]\dfrac{\overline{BC}}{\overline{AD}}= \dfrac{(\overline{AC})^2}{(\overline{BD})^2}=k[/tex]

Therefore:

[tex]\dfrac{\overline{AC}}{\overline{BD}}=\sqrt{k}[/tex]

Regards.
 
  • #3
mente oscura said:
Hello.

[tex]If \ \angle{A}=90º \ and \ \overline{BC} // \overline{AD} \rightarrow{}\angle{B}=90º[/tex]

[tex]If \ \overline{BC} // \overline{AD} \rightarrow{}\angle{ADB}=\angle{DBC}= \alpha[/tex]

[tex]\sin{\alpha}=\dfrac{\overline{AB}}{\overline{BD}}=\dfrac{\overline{BC}}{\overline{AC}}[/tex]

[tex]\cos{\alpha}=\dfrac{\overline{AB}}{\overline{AC}}=\dfrac{\overline{AD}}{\overline{BD}}[/tex]

Therefore:

[tex]\overline{AB}=\dfrac{\overline{BC} \ \overline{BD}}{\overline{AC}}[/tex]

[tex]\overline{AB}=\dfrac{\overline{AD} \ \overline{AC}}{\overline{BD}}[/tex]

[tex]\dfrac{\overline{BC} \ \overline{BD}}{\overline{AC}}=\dfrac{\overline{AD} \ \overline{AC}}{\overline{BD}}[/tex][tex]\dfrac{\overline{BC}}{\overline{AD}}= \dfrac{(\overline{AC})^2}{(\overline{BD})^2}=k[/tex]

Therefore:

[tex]\dfrac{\overline{AC}}{\overline{BD}}=\sqrt{k}[/tex]

Regards.
very good :)
 

Related to Finding $\dfrac{AC}{BD}$ of a Trapezoid $ABCD$

1. How do you find the value of AC/BD in a trapezoid?

The value of AC/BD in a trapezoid can be found by dividing the length of one of the diagonals (AC) by the length of the other diagonal (BD).

2. What tools or formulas are needed to calculate AC/BD in a trapezoid?

To calculate AC/BD in a trapezoid, you will need to know the lengths of both diagonals and use the formula AC/BD = AC/BD.

3. Is it possible for AC/BD to be greater than 1 in a trapezoid?

Yes, it is possible for AC/BD to be greater than 1 in a trapezoid. This means that the length of the diagonal AC is longer than the length of the diagonal BD.

4. Can AC/BD be negative in a trapezoid?

No, AC/BD cannot be negative in a trapezoid. This ratio is always positive, as diagonals of a trapezoid cannot be negative.

5. How does finding AC/BD in a trapezoid relate to its shape?

The value of AC/BD in a trapezoid can give insight into the shape of the trapezoid. If the value is close to 1, it means that the trapezoid is close to being a square. If the value is greater than 1, the trapezoid is more elongated, and if the value is less than 1, the trapezoid is wider.

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