Question

Match the figures to the number of threads of length 10 cm you should use to find their perimeters.

• A. 5
• B. 6
• C. 3

Answer 1

Length of the thread = 10 cm


Perimeter of the figure
$=15\text{cm}+10\text{cm}+15\text{cm}+10\text{cm}$
$=50\text{cm}$

If we are to measure the perimeter of the figure using threads of length 10 cm, then we would need $\frac{50}{10}=5$ threads.


Perimeter of the figure
$=5\text{cm}+20\text{cm}+15\text{cm}+20\text{cm}$
$=60\text{cm}$

$\therefore$ Number of threads needed $=\frac{60}{10}=6$


Perimeter of the figure
$=6\text{cm}+6\text{cm}+6\text{cm}+$
$6\text{cm}+6\text{cm}$
$=30\text{cm}$

$\therefore$ Number of threads needed
$=\frac{30}{10}=3$