मराठी

The length of AC is ______.

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प्रश्न

The length of AC is ______.

The image displays a geometric problem setup featuring a horizontal base segment $DC$ of length $60\text{ m}$, right angles at vertices $B, C,$ and $D$, a horizontal line segment $EB$, an angle of elevation of $30^{\circ}$ and an angle of depression of $45^{\circ}$ from vertex $E$.

पर्याय

  • \((60-20 \sqrt{3}) \mathrm{m}\)

  • \(60 \sqrt{3} \mathrm{~m}\)

  • \((60+20 \sqrt{3}) \mathrm{m}\)

  • \(20 \sqrt{3} \mathrm{~m}\)

MCQ
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उत्तर

The length of AC is \(\underline{\boldsymbol{(60+20 \sqrt{3}) \mathrm{m}}}\).

Explanation:

In rectangle BCDE,

Opposite sides of rectangle are equal.

\[\therefore BE = DC = 60\ \text{m}\]

We know that,

\[\tan \theta = \frac{\text{Perpendicular}}{\text{Base}}\]

From figure,

In \[\triangle ABE,\]

\[\Rightarrow \tan 30^\circ = \frac{AB}{BE}\]

\[\Rightarrow \frac{1}{\sqrt{3}} = \frac{AB}{60}\]

\[\Rightarrow AB = \frac{60}{\sqrt{3}} = 20\sqrt{3}\ \text{m}.\]

In \[\triangle EBC,\]

\[\Rightarrow \tan 45^\circ = \frac{BC}{BE}\]

\[\Rightarrow 1 = \frac{BC}{60}\]

\[\Rightarrow BC = 60\ \text{m}.\]

From figure,

\[AC = AB + BC = (20\sqrt{3} + 60)\ \text{m}.\]

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पाठ 22: Height and Distances - TEST YOURSELF [पृष्ठ ३५३]

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सेलिना Concise Mathematics [English] Class 10 ICSE
पाठ 22 Height and Distances
TEST YOURSELF | Q 1. (c) | पृष्ठ ३५३
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