Question

Area of a rectangle is 21 cm². If length of the rectangle is 3 cm.
i) Perimeter of the rectangle
ii) Area of rectangle​

Answer 1

Answer:

I)Perimeter of the rectangle is 20 cm

Ii)Area of the rectangle is 21 cm^3

Step-by-step explanation:

Area of rectangle is 21 cm^3(given)

think so, The width of the rectangle is 'a'

and the length of the rectangle is 3 cm

so, a × 3 = 21

for that, a = 21÷3 = 7 cm.

i) so, The perimeter of the rectangle is 2(3+7)=20cm

ii) The area of rectangle is 21 cm^3(given).

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Answer 2

Answer:

Given :-

• The area of a rectangle is 21 cm².
• The length of the rectangle is 3 cm.

To Find :-

• What is the perimeter of the rectangle.
• What is the area of a rectangle.

Solution :

First, we have to find the breadth of a rectangle :

Given :

• Area of Rectangle = 21 cm²
• Length = 3 cm

According to the question by using the formula we get,

$\small \implies \sf\boxed{\bold{Area_{(Rectangle)} =\: Length \times Breadth}}$

$\implies \sf 21 =\: 3 \times Breadth$

$\implies \sf \dfrac{21}{3} =\: Breadth$

$\implies \sf 7 =\: Breadth$

$\implies \sf\bold{Breadth =\: 7\: cm}$

Hence, the breadth of a rectangle is 7 cm .

Now, we have to find the perimeter of the rectangle :

Given :

• Length = 3 cm
• Breadth = 7 cm

According to the question by using the formula we get,

$\footnotesize \implies \sf\boxed{\bold{Perimeter_{(Rectangle)} =\: 2(Length + Breadth)}}$

$\implies \sf Perimeter_{(Rectangle)} =\: 2(3 + 7)$

$\implies \sf Perimeter_{(Rectangle)} =\: 2 \times 10$

$\implies \sf\bold{\underline{Perimeter_{(Rectangle)} =\: 20\: cm}}$

$\therefore$ The perimeter of a rectangle is 20 cm .

Now, we have to find the area of a rectangle :

Given :

• Length = 3 cm
• Breadth = 7 cm

According to the question by using the formula we get,

$\small \implies \sf\boxed{\bold{Area_{(Rectangle)} =\: Length \times Breadth}}$

$\implies \sf Area_{(Rectangle)} =\: 3\: cm \times 7\: cm$

$\implies \sf Area_{(Rectangle)} =\: (3 \times 7)\: cm^2$

$\implies \sf\bold{\underline{Area_{(Rectangle)} =\: 21\: cm^2}}$

$\therefore$ The area of a rectangle is 21 cm² .