Question

The length of a rectangular field is thrice its breadth and its perimeter is 240 m. The length of the field is?

Answer 1

To find : area of rectangular field.

Given : perimeter = $240\ m$  ,  

           The length of a rectangular field is thrice its breadth .

Solution :

• According to question we are given that length of a rectangular field is thrice its breadth .
• Let ,breadth of rectangle be x , then length be $3x$ .

• To find perimeter  we use following formula -

       Perimeter =  $2 ( l + b )$

• Substituting the values we get,

         $240 = 2 ( 3x + x ) \\ 240 = 2 \times 4x \\240 = 8x \\x = 30$

• Then , breadth of field = $x = 30 cm$
• length of field = $3x = 3 \times 30 = 90\ cm$

Hence, length of  rectangular field is $90 cm$ .

Answer 2

Question

The length of a rectangular field is thrice its breadth and its perimeter is 240 m. Find the length of the field.

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Elucidation

Let the required length of a rectangular field be 'L' while its breadth be 'B' .

Perimeter of Rectangular Field = 240 m.

✸ General formula for Perimeter of Rectangle

Perimeter of Rectangle = 2(l + B)

♣ According to the question

L = 3 × B

Substitute the value in the formula for Perimeter.

Perimeter of Rectangle = 2(3B + B)

Perimeter of Rectangle = 2(4B)

Perimeter of Rectangle = 8B

Perimeter of Rectangle = 240 m

8B = 240

B = 240/8 = 30 m

Here we get Breadth of Rectangle. Now what's asked in the question is Length

We know that,

L = 3 × 30

L = 90 m

The Required Length of rectangle is 90m

Hence Calculated !!

Illustrated Diagram of Rectangular Field with required dimensions :

$\begin{gathered}\begin{gathered} \sf{ \pink{30 \: m }\:}\huge\boxed{ \begin{array}{cc} \: \: \: \: \: \: \: \: \: \: \sf\large{240 \: m^{} }\\ \: \: \: \: \: \: \: \: \: \end{array}} \\ \: \: \: \: \: \sf{ \orange{90 \: m}}\end{gathered} \end{gathered}$

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