Question

Area of the circle is 38.5 cm^2. Find the circumference.​

Answer 1

Given :-

• Area of the circle is 38.5 cm^2.

To Find :-

• Find the circumference.

Solution :-

~Here, we’re given the area of a circle and we need to find the circumference of that circle. Firstly we will find the radius of the circle by putting the values in the formula of area of circle. After getting the radius we can easily find the circumference by applying it’s formula.

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As we know that ,

$\boxed{\sf{ \maltese \;\; Area\;of\;circle = \pi r^{2} }}$

$\boxed{\sf{ \maltese \;\; Circumference = 2 \pi r }}$

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Finding the radius :-

$\sf \implies \pi r^{2} = 38.5 \;cm^{2}$

$\sf \implies \dfrac{22}{7} \times r^{2} = 38.5$

$\sf \implies r = \sqrt{38.5 \div \dfrac{22}{7}}$

$\boxed{\bf{ \bigstar \;\; Radius = 3.5 \;cm}}$

Finding the circumference :-

$\sf \implies 2 \times \dfrac{22}{7} \times 3.5$

$\sf \implies 2 \times \dfrac{22}{7} \times \dfrac{35}{10}$

$\sf \implies \dfrac{220}{10}$

$\boxed{\bf{ \bigstar \;\; Circumference = 22\;cm }}$

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Hence,

The circumference of that circle is 22 cm  

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Answer 2

$\huge{\dag\:{\underline{\boxed{\mathfrak{\pink{Answer}}}}}}$

Given:

• Area of circle is 38.5cm²

To find:

• Circumference of the circle

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➦ Area of circle = πr²

➦ 38.5 = πr²

$➦ \frac{22}{7} \times r² = 38.5$

$➦ r² = 38.5 \times \frac{7}{22}$

$➦ r² = 12.25$

$➦ r = \sqrt{12.25}$

$➦ r = 3.5$

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● Now circumference of circle is= 2πr

$● circumference \: of \: circle \: = 2 \times \frac{22}{7} \times \frac{35}{10}$

● Circumference of circle is 22m.