# Surface Area of Sphere

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Determining the expressions for the surface area of a sphere requires a more detailed analysis, so we will not discuss those here. Instead, for now you are expected to simply memorize these expressions:

• SA of sphere = $$4\pi {r^2}$$

• Curved SA of hemisphere = $$2\pi {r^2}$$

• Flat SA of hemisphere = $$\pi {r^2}$$

• Total SA of hemisphere= $$\left\{ \begin{array}{l} 2\pi {r^2} + \pi {r^2}\\ 3\pi {r^2} \end{array} \right.$$

Example 1: Find the surface area of a sphere of radius 5 cm.

Solution: We have:

\begin{align}&SA = 4\pi {r^2} \approx 314\,{\rm{c}}{{\rm{m}}^2}\end{align}