Question

How can you use a formula for one measurement to write a formula for a different measurement?

Answer 1

Write the formula for one measurement, then solve the formula for the different measurement you want to find and use this new formula to find that measurement.

Explanation:

We can understand this through an example.

If we need to find the lenght of a rectangle whose width is 4 feet and whose perimeter is 28 feet, we can use a formula for one measurement to write a formula for a different measurement:

- We need to write the formula for the perimeter of a rectangle:

`P=2l+2w`

Where "l" is the lenght and "w" is the width.

- Since we know the width and the perimeter of the rectangle and we need to find the lenght, we can solve for "l":

`P=2l+2w\\\\P-2w=2l\\\\l=(P-2w)/(2)`

Now we get a new formula for calculate a differente measurement (the lenght of the rectangle).

- Substituting values, we get:

`l=(28ft-2(4ft))/(2)=10\ ft`