The surface area (in ${\text{cm}}^2$) of a sphere, whose diameter is $42\text{ cm}$, is: (Take $\pi =\frac{22}{7}$)

Given the diameter of the sphere is $42\text{ cm}$.Therefore, the radius $r=\frac{42}{2}=21\text{ cm}$.The formula for the total surface area of a sphere is:
$$\text{Surface Area}=4\pi r^2$$
Substituting the values:
$$\text{Surface Area}=4\times \frac{22}{7}\times 21\times 21$$
$$\text{Surface Area}=4\times 22\times 3\times 21$$
$$\text{Surface Area}=88\times 63=5544{\text{ cm}}^2$$