Question

Find the length of the rectangle if the perimeter
and width are :
(a) Perimeter = 86 cm, width = 18 cm
(b) Perimeter = 128 cm, width = 25 cm
) Perimeter = 151 cm, width = 29.5 cm
1​

Answer 1

Step-by-step explanation:

perimeter of the rectangle is 2(l+b).

so (perimeter/2) -breadth = length

(a) (86/2) - 18 = 25

(b) (128/2) -25 = 39

(c) (151/2) - 29.5 = 46.

PLEASE MARK THE BRAINLIEST

Answer 2

question:-

Find the length of the rectangle if the perimeter and wide are:

1. perimeter = 86cm, width = 18cm
2. perimeter = 128cm, width = 25cm
3. perimeter = 151cm, width = 29.5cm

solution:-

1. $\underline\pink{length = 25}$
2. $\underline\orange{length = 39}$
3. $\underline\green{length = 46}$

let's find out !!

using formula :-

$p = 2(l + b)$

1. we have:

>> perimeter = 86cm

>> length = l

>> wide = 18cm

$\pink {= 2(l + b) = perimeter}$

$\pink {= 2(l + 18) = 86}$

$\pink{= 2l + 36 = 86}$

$\pink{= \: 2l = 86 - 36}$

$\pink{= 2l = 50}$

$\pink {= l = \frac{50}{2} }$

$\pink {= l = 25}$

<<hence the length of the rectangle is 25cm>>

________________________

2. we have

>> perimeter = 128cm

>> width = 25cm

>> length = l

so,

$\orange{= 2(l + b) = perimeter}$

$\orange{= 2( l+ 25) = 128}$

$\orange{= 2l + 50 = 128}$

$\orange{= 2l = 128 - 50}$

$\orange{= 2l = 78}$

$\orange{= l = \frac{78}{2} }$

$\orange{l = 39}$

hence the length of the rectangle is 39cm.

________________________

3. we have

>> perimeter = 151cm

>> width = 29.5cm

>> length = l

so,

$\green{= 2(l + b) = perimeter}$

$\green{= 2(l + 29.5) = 151}$

$\green{= 2l + 59 = 15}$

$\green{= 2l = 151 - 59}$

$\green{= 2l = 92}$

$\green{= l = \frac{92}{2} }$

$\green{=l = 46cm}$

hence the length of the rectangle is 46cm