Pre-Algebra Examples

 $\begin{array}{r} r = & 4 in \end{array}$

Step 1

The surface area of a sphere is equal to $4$ times Pi $π$ times the radius squared.

$4 π \cdot {(r a d i u s)}^{2}$

Step 2

Substitute the value of the radius $r = 4$ into the formula to find the surface area of the sphere. Pi $π$ is approximately equal to $3.14$ .

$4 \cdot π \cdot 4^{2}$

Step 3

Multiply $4$ by $4^{2}$ by adding the exponents.

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Step 3.1

Move $4^{2}$ .

$4^{2} \cdot 4 \cdot π$

Step 3.2

Multiply $4^{2}$ by $4$ .

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Step 3.2.1

Raise $4$ to the power of $1$ .

$4^{2} \cdot 4^{1} \cdot π$

Step 3.2.2

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$4^{2 + 1} \cdot π$

Step 3.3

Add $2$ and $1$ .

$4^{3} \cdot π$

Step 4

Raise $4$ to the power of $3$ .

$64 π {(in)}^{2}$