Question

5. The breadth of a rectangle is 42 m. If its length is 3
times its breadth, find the perimeter of the rectangle.​

Answer 1

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Answer 2

Perimeter = 42 cm

Length = 3 cm less than thrice its breadth

To find :

Its dimensions

Solution :

Let the -

Breadth be y

Length be (3y - 3)

${\tt{Perimeter=2(Length+Breadth)}} </p><p>$

$\begin{gathered}\tt{\implies} \: 2(y + 3y -3) = 42 \\ \\ \tt{\implies} \:2(4y - 3) = 42 \\ \\ \tt{\implies} \:8y - 6 = 42 \\ \\ \tt{\implies} \:8y = 42 + 6 \\ \\ \tt{\implies} \:8y = 48 \\ \\ \tt{\implies} \:y = \dfrac{48}{8} \\ \\ \tt{\implies} \:y = 6\end{gathered}$

Breadth = 6 cm

★ Value of (3y - 3)

$\begin{gathered}\tt{\implies} \:3(6) - 3 \\ \\\tt{\implies} \:18 - 3 \\ \\ \tt{\implies} \:15\end{gathered} </p><p>$

Length = 15 cm

The Length is 15 cm and Breadth is 6 cm.