Question:
Will it be true to say that the perimeter of a square circumscribing a circle of radius a cm is 80 cm? Give reason for your answer.
Solution:
True
Given, radius of circle, $r=\mathrm{a} \mathrm{cm}$
$\therefore$ Diameter of circle, $d=2 \times$ Radius $=2 \mathrm{acm}$
$\therefore \quad$ Side of a square $=$ Diameter of circle
$=2 \mathrm{a} \mathrm{cm}$
$\therefore$ Perimeter of a square $=4 \times($ Side $)=4 \times 2 \mathrm{a}$
$=8 \mathrm{a} \mathrm{cm}$