Question

What is the area of a circle with a diameter of 20cm?

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Answer 1

$\sf\underline{Answer-}$

• $\sf\underline{Area \:of\: the \:circle\: is\: 314.15cm^2}$

$\sf\huge{ Explanation -}$

$\sf\underline{Given:-}$

• $\sf{Diameter \: of \: circle \: is : 20cm}$
• $\pi = 3.1415$

$\sf\underline{To \: find:-}$

• What is the area of the circle?

$\sf\underline{Formula \: used :-}$

• $\sf{radius=}\dfrac{Diameter}{2}$

• $\sf{area = π r^2}$

STEP-1 :Finding the radius of the circle -

$\sf{According \: to \: the \: question-}$

$\sf{☆radius =}\dfrac{Diameter}{2}$

$\sf{☆radius =}\dfrac{20}{2}$

$\sf{☆radius = 10cm}$

Step-2:Finding the area of the circle -

$\implies$ $\sf{Area= πr^2}$

$\implies$ $\sf{3.1415(10)^2}$

$\implies$ $\sf{3.1415 \times 10^2}$

$\implies$ $\sf{ 3.1415 \times 10 \times 10}$

$\implies$ $\sf{3.1415 \times 100}$

$\implies$ $\sf{Area = 314.15}$

$\sf\blue{Hence , proved!}$

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Answer 2

Answer :-

• The area of the circle is 314.2 cm².

To find :-

• The area of a circle with a diameter of 20 cm.

Step-by-step explanation :-

• Before finding the area of the circle, we have to find it's radius!

We know that :-

$\underline{\boxed{\sf Radius = \dfrac{Diameter}{2}}}$

Here,

• Diameter = 20 cm.

Therefore,

$\mapsto \bf Radius = \dfrac{20}{2}$

$\mapsto \bf Radius = 10 \: cm$

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• Now let's find the area of the circle!

We know that :-

$\underline{\boxed{\sf Area \: of \: a \: circle = \pi r^2}}$

Where,

• r = Radius.

Here,

• Radius = 10 cm.
• π = 22/7.

Therefore,

$\dashrightarrow \rm Area = \dfrac{22}{7} \times 10^2$

$\dashrightarrow \rm Area = \dfrac{22}{7} \times 100$

$\dashrightarrow \rm Area = \dfrac{2200}{7}$

$\dashrightarrow \rm Area = 314.2 \: cm^2$

Hence :-

• The area of the circle is 314.2 cm².

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