Question

If the radius of a circle is at least $7\text{cm}$, then the minimum area of the circle is : (in $\text{sq. cm}$) $(\text{use}\pi =\frac{22}{7})$

• A. $154$
• B. $0$
• C. $49$
• D. $21$

Answer 1

The correct option is A $154$

$r\ge 7$
$\Rightarrow r^2\ge 49$
$\Rightarrow \pi r^2\ge 49\pi$
Area $\ge 49\times \frac{22}{7}$
Area $\ge 154$
$\Rightarrow$ least area is $154\text{sq. cm}$