Find the Surface Area box (3)(7)(5)

 $\begin{array}{r} h = & 3 \\ l = & 7 \\ w = & 5 \end{array}$

Step 1

The surface area of a box is equal to the sum of the areas of each side of the box.

$2 \cdot (l e n g t h) \cdot (w i d t h) + 2 \cdot (l e n g t h) \cdot (h e i g h t) + 2 \cdot (w i d t h) \cdot (h e i g h t)$

Step 2

Substitute the values of the length $l = 7$ , the width $w = 5$ , and the height $h = 3$ into the formula.

$2 \cdot 7 \cdot 5 + 2 \cdot 7 \cdot 3 + 2 \cdot 5 \cdot 3$

Step 3

Simplify each term.

Multiply $2 \cdot 7 \cdot 5$ .

Multiply $2$ by $7$ .

$14 \cdot 5 + 2 \cdot 7 \cdot 3 + 2 \cdot 5 \cdot 3$

Multiply $14$ by $5$ .

$70 + 2 \cdot 7 \cdot 3 + 2 \cdot 5 \cdot 3$

Multiply $2 \cdot 7 \cdot 3$ .

Multiply $2$ by $7$ .

$70 + 14 \cdot 3 + 2 \cdot 5 \cdot 3$

Multiply $14$ by $3$ .

$70 + 42 + 2 \cdot 5 \cdot 3$

Multiply $2 \cdot 5 \cdot 3$ .

Multiply $2$ by $5$ .

$70 + 42 + 10 \cdot 3$

Multiply $10$ by $3$ .

$70 + 42 + 30$

Step 4

Simplify by adding numbers.

Add $70$ and $42$ .

$112 + 30$

Add $112$ and $30$ .

$142$