Question

What is the surface area of the cube?
20x10x9

Answer 1

To find the surface area of a cube, you first need to determine the side length of the cube. However, it seems you have provided dimensions of a rectangular prism (20, 10, and 9) rather than a cube.

For a rectangular prism with dimensions length \( l = 20 \), width \( w = 10 \), and height \( h = 9 \), the surface area \( A \) can be calculated using the formula:

\[
A = 2(lw + lh + wh)
\]

Substituting in the given dimensions:

\[
A = 2(20 \cdot 10 + 20 \cdot 9 + 10 \cdot 9)
\]

Calculating each term:

\[
lw = 20 \cdot 10 = 200
\]
\[
lh = 20 \cdot 9 = 180
\]
\[
wh = 10 \cdot 9 = 90
\]

Now, sum these areas:

\[
lw + lh + wh = 200 + 180 + 90 = 470
\]

Finally, multiply by 2 to find the total surface area:

\[
A = 2 \cdot 470 = 940
\]

So, the surface area of the rectangular prism is \( 940 \) square units.