Question

If the perimeter and breadth of a rectangle are 40cm and 9cm respectively.Find it's length​

Answer 1

Answer:

Step-by-step explanation:

Let "L" be length and "b" be breadth of the rectangle.

Breadth = 9 cm

Perimeter = 2 ( L + b ) = 40 cm

                =2 ( L + 9 ) = 40

                = L + 9 = 40÷2=20

∴Length = 20 - 9 = 11 cm

Answer 2

$\begin{gathered}{\large{\textsf{\textbf{\underline{\underline{Given:-}}}}}}\end{gathered}$

• Perimeter = 40cm
• breadth = 9cm

$\begin{gathered}{\large{\textsf{\textbf{\underline{\underline{To find:-}}}}}}\end{gathered}$

• Length

$\begin{gathered}{\large{\textsf{\textbf{\underline{\underline{Formula required:-}}}}}}\end{gathered}$

• Perimeter=2( L + B )

$\begin{gathered}{\large{\textsf{\textbf{\underline{\underline{basic \: terms \: :-}}}}}}\end{gathered}$

• Perimeter is the distance around the edge of a shape.
• Length is a measure of distance
• Breadth is a measurement from side to side of something.

$\begin{gathered}{\large{\textsf{\textbf{\underline{\underline{solution:-}}}}}}\end{gathered}$

Here,

• Perimeter = 40cm
• breadth = 9cm

❥Let the length be l.

★ Calculating the length of rectangle.

${\begin{gathered}\begin{gathered}\mapsto\rm perimeter = 2( l \: + \: b )\rm \end{gathered} \end{gathered} }$

• Substituting the values.

${\begin{gathered}\begin{gathered}\mapsto\rm 40cm= 2(l+ \: 9cm )\rm \end{gathered} \end{gathered} }$

${\begin{gathered}\begin{gathered}\mapsto\rm 40cm= 2l+ \: 18cm )\rm \end{gathered} \end{gathered} }$

${\begin{gathered}\begin{gathered}\mapsto\rm 2l=40 - 18cm )\rm \end{gathered} \end{gathered} }$

${\begin{gathered}\begin{gathered}\mapsto\rm 2l= 22cm \rm \end{gathered} \end{gathered} }$

${\begin{gathered}\begin{gathered}\mapsto\rm l= \cancel\frac{22cm}{2} \rm \end{gathered} \end{gathered} }$

${\begin{gathered}\begin{gathered}\mapsto\rm l= 11cm \rm \end{gathered} \end{gathered} }$

${\therefore{\underline{\underline{\pmb{\frak {The \: length \: of \:the \: rectangle\: is \: {\sf{\red{ 11cm.}}}}}}}}}\begin{gathered}\end{gathered}$