Question

A large rectangle is made up of elevenidentical rectangles whose longer sides are 21cm long. The perimeter of the large rectanglein cm isA) 150B) 126C) 108​

Answer 1

Answer:

Option (A) 150

Step-by-step explanation:

The figure is attached.

Let the length of the rectangle is L and breadth is B then

L = 21 cm

From the figure we can see that the length of 2 rectangles is equal to the breadth of 7 rectangles

Therefore,

$2L=7B$

$\implies 2\times 21=7B$

$\implies B=2\times \frac{21}{7}=6\text{ cm}$

The length of the bigger rectangle

$L'=2L=2\times 21=42\text{ cm}$

The breadth of the rectangle

$B'=L+2B=21+2\times 6=21+12=33\text{ cm}$

The perimeter of this rectangle

$P=2(L'+B')$

$\implies P=2(42+33)$

$\implies P=2\times 75$

$\implies P=150\text{ cm}$

Therefore, the perimeter of large rectangle is 150 cm

Hope this helps.