8. A rectangle is measured to be 6.4 +0.2 cm by 8.3 $0.2 cm. a) Calculate its perimeter in cm

b) Calculate the uncertainty in its perimeter.

a) The perimeter of the rectangle is 29.4 centimeters.

b) The uncertainty in its perimeter is 0.8 centimeters.

Explanation:

a) From Geometry we remember that the perimeter of the rectangle (), measured in centimeters, is represented by the following formula:

(1)

Where:

- Width, measured in centimeters.

- Length, measured in centimeters.

If we know that and , then the perimeter of the rectangle is:

The perimeter of the rectangle is 29.4 centimeters.

b) The uncertainty of the perimeter (), measured in centimeters, is estimated by differences. That is:

 (2)

Where:

- Uncertainty in width, measured in centimeters.

- Uncertainty in length, measured in centimeters.

If we know that and , then the uncertainty in perimeter is:

The uncertainty in its perimeter is 0.8 centimeters.