If the total surface area  of solid sphere is 98.56 cm square are then find the radius of the sphere.

Answer :

Given total surface area of solid sphere  = 98.56 cm²
And
We know Total surface area of sphere  = $4 \mathrm{\pi } {\mathrm{r}}^2$
Here r  =  Radius of sphere
So,
$$\begin{gathered} 4 \mathrm{\pi } {\mathrm{r}}^2 = 98.56 \\ \Rightarrow 4 \times \frac{22}{7}\times {\mathrm{r}}^2 = 98.56 \\ \Rightarrow 88\times {\mathrm{r}}^2 = 98.56\times 7 \\ \Rightarrow 88\times {\mathrm{r}}^2 =689.92 \\ \Rightarrow {\mathrm{r}}^2 =\frac{689.92}{88} \\ \Rightarrow {\mathrm{r}}^2 =7.84 \\ \Rightarrow \mathrm{r} =2.8 \end{gathered}$$
So,
Radius of sphere  =  2.8 cm                                          ( Ans )