Question

The surface area of a cell phone screen is 6800 mm2. Use the fact that 10 mm = 1 cm to convert this area to cm2. Round your answer to the nearest whole number. Do not type the units in the space below.

Answer 1

`68 \: {cm}^(2)`

Explanation:

You can use 1 cm = 10 mm very well to help you with this.

The small two at the end of the unit (cm^2) refers, that the shape of an object is two dimensional. If we make 1 cm two dimensional by multiplying it with the original 1 cm, we get a total area of

`1 \: {cm} * 1 \: {cm} \: = 1 \: {cm}^(2)`

We have created an equation. Since we know 1 cm = 10 mm, we can replace the centimetres in the equation with the millimetres, like so:

`10 \: mm * 10 \: mm = 1 \: {cm}^(2) \\ 100 \: {mm}^(2) = 1 \: {cm}^(2)`

From there, its just a simple matter of calculation:

`6800 \: {mm}^(2) * \frac{1 \: {cm}^(2) }{100 \: {mm}^(2) } = 68 \: \: {cm}^(2)`