Question

Find the surface area of a sphere of radius 21 cm
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Answer 1

Answer:

=> The surface area of a sphere is $5544cm^2.$

Step-by-step explanation:

Given that:-

Radius = $21$ cm

To find:- The surface area of a sphere

The formula is used to calculate,

The surface area of a sphere = $4\pi r^2$

                                                = 4 $\times$ $\frac{22}{7}$ $\times$ 21 $\times$ 21

                                                = 4 $\times$ 22 $\times$ 3 $\times$ 21

                                                = $5544cm^2$

Hence, the surface area of a sphere is $5544cm^2.$

Answer 2

As per the given data in the question

In the above question it is given that

We have find the value of given expression

Given surface area of a sphere of radius is $21cm$

We have used to formula and determine the value

The surface area of the sphere $=4\pi r^{2}$

$\Rightarrow 4*\frac{22}{7} *21^{2} \\\Rightarrow 4*\frac{22}{7} *441\\\Rightarrow 4*3.1428*441\\\Rightarrow 5544cm^{2}$

Hence the required value of surface area will be $5544 cm^{2}$