Question

find the radius of a circle whose area is 49 π cm​

Answer 1

Radius of given circle=5cm

Therefore,

Area of given circle=π(5)

2

=25πcm

Let,radius of required circle=r

Therefore,

πr

2

=49×25π

=>r

2

=(7×5)

2

=>r=35

Therefore,

Circumference=2πr

=2×

7

22

×35

=220m

Step-by-step explanation:

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Answer 2

Answer:

The radius of a circle is $7$ cm.

Step-by-step explanation:

Given : Area of a circle = $49\pi$ $cm^{2}$

To find : The radius of a circle.

Solution :

• It is given that the area of a circle = $49\pi$ $cm^{2}$
• We have to find the radius of a circle.
• Let, $r$ be the radius of a circle.
• Circle is a closed figure having a set of points at equal distance from the center of a circle.

• The formula for area of a circle is given by,

        Area of a circle = $\pi r^{2}$

                         ∴ $49\pi =\pi r^{2}$      

                          ∴ $\frac{49\pi }{\pi } =r^{2}$

                          ∴ $r^{2} =49$

• Taking square roots of both the sides, we get

                           ∴ $r=7$ cm

• ∴ The radius of a circle is $7$ cm.