Question

5) If the area of circle is 154 sq cm, then its perimeter is: a) 11 cm b) 22 cm c) 44 cm d) 55cm​

Answer 1

$\mathtt{\huge{\bf{\underline{\red{Answer :-}}}}}$

➝ 44 cm

$\mathtt{\huge{\bf{\underline{\green{Explaination :-}}}}}$

$\sf{\huge{\underline{\pink{Given :-}}}}$

• The area of circle is 154 sq cm.

$\sf{\huge{\underline{\purple{To\:Find :-}}}}$

• The perimeter of circle.

$\sf{\huge{\underline{\orange{Solution :-}}}}$

We know , the area of circle is = $\pi {r}^{2}$

Where , r is the radius of circle.

We have given the area of circle is 154 sq cm.

So, $\pi {r}^{2}$ = 154 sq.cm.

➝ r² = $\dfrac{154}{\pi}$

➝ r² = $\dfrac{154 × 7}{22}$

➝ r² = $\cancel{\dfrac{1078}{22}}$

➝ r² = 49

➝ r = √49

➝ r = 7cm.

So, we get our radius r = 7cm.

We know that ,

The perimeter of circle = circumferance of circle = 2$\pi$ r

➝ 2$\pi$ r

➝ 2 × $\dfrac{22}{7}$ × 7

➝ 2 × 22

➝ 44 cm

So, we get The perimeter of circle = 44cm.

$\setlength{\unitlength}{1cm}\begin{picture}(0,0)\thicklines\qbezier(2.3,0)(2.121,2.121)(0,2.3)\qbezier(-2.3,0)(-2.121,2.121)(0,2.3)\qbezier(-2.3,0)(-2.121,-2.121)(0,-2.3)\qbezier(2.3,0)(2.121,-2.121)(-0,-2.3)\put(0,0){\line(1,0){2.3}}\put(0.5,0.3){\bf\large x\ cm}\end{picture}$