Question

Find the surface area of a sphere of diameter 3.5 cm

Answer 1

Hint: To answer these types of question perfection in calculation is must, it is important to remember the formula of surface area of the sphere and use these instructions to approach towards the solution of the question.

Complete step-by-step answer:
According to the given information about the problem we have a sphere with diameter 3.5 cm as shown in diagram below

As we know that the sphere is the 3D representation of shapes which have some properties like it have a symmetrical shape, the distance from the center of the sphere to all points on the surface of the surface is equal which is named as the radius of the sphere
Whereas the diameter is the measure of the distance between the 2 opposite points on the surface of the sphere
We know that the surface of the sphere is calculated by the formula $A = 4\pi {r^2}$
So since we have diameter i.e. D = 3.5cm
Therefore radius of the sphere is equal to (diameter)/2 i.e. $r = \dfrac{D}{2}$
Substituting the value of diameter in the formula above
$r = \dfrac{{3.5}}{2}$ = 1.75 cm
Now substituting the value of radius in the formula of surface area of sphere
$A = 4\pi {\left( {1.75} \right)^2}$
We know that $\pi = \dfrac{{22}}{7}$
Therefore $A = 4 \times \dfrac{{22}}{7}{\left( {1.75} \right)^2}$
$ \Rightarrow $$A = 4 \times \dfrac{{22}}{7} \times 3.0625$
$ \Rightarrow $$A = 38.5c{m^2}$
Hence the surface of the sphere of diameter 3.5 is equal to$38.5c{m^2}$.

Note: In the above question we found the surface area of sphere so in mathematics we say that the total amount of space occupied by the 3D object is called surface area of that object whereas the volume of a 3D object is the measure of part occupied by the 3D object, these terms are used to measure or to determine the amount of object or to determine one of the physical property of the 3D shapes of objects.