Question

I want this question step by step explanation pls help​

Answer 1

Answer :

Option (D) = 12 m is correct.

Solution :

{ Refer to the attachment for the diagram }

Let, the two poles are AB and CD

where AB = 18 m and CD = 12 m

Let, AC is the wire

Here, EB || CD thus EB = CD

So, EB = 12 m

Thus, AE = AB - EB = 18 - 12 m = 6 m

We know that, tan30° = $\frac{1}{\sqrt{3}}$

  ⇒ $\frac{AE}{EC} = \frac{1}{\sqrt{3}}$

  ⇒ EC = AE √3

  ⇒ EC = 6√3

We see that, triangle ΔAEC is right angled, so by Pyathagorean Theorem, we get

  AE² + EC² = AC²

  ⇒ 6² + (6√3)² = AC²

  ⇒ AC² = 36 + 108

  ⇒ AC² = 144

  ⇒ AC² = 12²

  ⇒ AC = ± 12

Since, length cannot be negative,

AC = 12 m

∴ the length of the wire is 12 m

Answer 2

Answer:

12 m

Step By Step Explanation:

Given:

First Pole's Height = AB = 18 m

Second Pole's Height = CD = 12 m

Length of the wire = AD

From The Condition:

AE = AB - BE
⇒ AB - CD
⇒ 18 - 12
⇒ 6 m

Hence, Length Of AE is 6 m.

Now,
In ∆ AED ,

∠ AED = 90° ,

∠ ADE = 30° [ Given ]

We have,
Sin 30° = AE/AD

⇒ 1/2 = 6/AD

⇒ AD = 6 × 2

⇒ AD = 12 m

Hence, The Required length of the wire is 12 m.