Question

We cut out squares(white) of side 10 cm from a square of side 40 cm. Match the new shapes to their perimeters.

• A. 160 cm
• B. 200 cm
• C. 180 cm

Answer 1

The perimeter of the square of side 40 cm is $4\times 40\text{cm}=160\text{cm}.$

We know that the perimeter of the shape got when a square is cut out from all four corners of a larger square is equal to the perimeter of the larger square.



$\therefore$ Perimeter of the above shape is 160 cm.


The perimeter of the shape on the right in the above image is

$40\text{cm}+40\text{cm}+40\text{cm}+20\text{cm}+10\text{cm}+10\text{cm}+10\text{cm}+10\text{cm}$
$=180\text{cm}.$


The perimeter of the shape on the right in the above image is

$40\text{cm}+40\text{cm}+20\text{cm}+20\text{cm}+10\text{cm}+10\text{cm}+10\text{cm}+10\text{cm}+10\text{cm}+10\text{cm}+10\text{cm}+10\text{cm}$
$=200\text{cm}.$