Question

Length of a rectangle is three times its breadth. Perimeter of the rectangle is 40 cm. Find its
length and width.
​

Answer 1

Answer:

x = 3.64

Step-by-step explanation:

let the length be = 3x

let the breadth be = x

perimeter of rectangle = l × b

40cm = 3x × x

40cm = 3x^2

40 / 3 = x^2

13.3 = x^2

_/ 13.3 = x

3.64... = x

x = 3.64

Answer 2

$\mathfrak{ \large{ \pink{ \underline{ \orange{Correct \: Question: }}}}}$

Length of a rectangle is three times its breadth. Perimeter of the rectangle is 40 cm. Find its length and width.

$\mathfrak{ \large{ \pink{ \underline{ \orange{ Given: }}}}}$

• Perimeter of rectangle = 40 cm
• Length is three times the breadth of rectangle

$\mathfrak{ \large{ \pink{ \underline{ \orange{ To \: Find : }}}}}$

• Length and breadth of rectangle

$\mathfrak{ \large{ \pink{ \underline{ \orange{ Solution: }}}}}$

• Let the breadth of rectangle be x
• The length of rectangle will be 3x

$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\ \mathfrak { \underline{ \green{Formula\: to\: calculate\: perimeter\: of\: rectangle}}}$

$\boxed{ \boxed{ \mathfrak{ \large{ \red{perimeter = 2(length + breadth)}}}}}$

According to question,

$\large{ \sf \longmapsto \: \: \: \: \: \: \: \: \: 2(x + 3x) = 40}$

$\large{ \sf \longmapsto \: \: \: \: \: \: \: \: \:2(4x) = 40}$

$\large{ \sf \longmapsto \: \: \: \: \: \: \: \: \:4x = \frac{40}{2} }$

$\large{ \sf \longmapsto \: \: \: \: \: \: \: \: \:4x = 20}$

$\large{ \sf \longmapsto \: \: \: \: \: \: \: \: \:x = \cancel\frac{20}{4} }$

$\large{ \sf \longmapsto \: \: \: \: \: \: \: \: \boxed{ \purple{ \underline{ \mathfrak{x = 5}}}}}$

Now,

• Length of rectangle = 3x = 15 cm
• Breadth of rectangle = x = 5 cm

$\mathfrak{ \large{ \pink{ \underline{ \orange{ Hence: }}}}}$

The length and breadth of rectangle are 15 cm and 5 cm.