Hello there,
In order to solve this problem we need to first write down what do we already know based on what is given:
- the length is 9 cm
- the width is 28 mm
- we are solving for the perimeter of the rectangle
Now that we established what is given, now we need to make sure that our unis match up:
**Remember that you can not add any two values that do not have the same units.**
Since the length is in cm and the width is in mm we need to change the width so that it has the same unit as the length.
- 1 cm is 10 mm therefore, 28 mm is 2.8 cm
Now that we have the same units we can use the equation, 2(l + w), to find the perimeter.
2(9 + 2.8) = 2(11.8) = 23.6 cm.
If the rectangle had the length of 9 cm and the width is 28 mm the perimeter would be 23.6 cm.
Hope I helped,
Amna
