Question

Given the area $a$ of a circle is $154uni{t}^2$, what is its radius $r$?

• A. $r=5units$
• B. $r=6units$
• C. $r=7units$
• D. $r=8units$

Answer 1

The correct option is C $r=7units$

$a=\pi r^2$
$\Rightarrow 154=\frac{22}{7}\times r^2$
$\Rightarrow \frac{154\times 7}{22}=r^2$
$\Rightarrow r^2=7^2$
or, $r=7$ units