Posted by Jeff on .
the lenght of a rectangle is fixed at 19 cm. What width will make perimeter greater than 70 cm?

Algebra 
jim,
The perimeter is two lengths + two widths, and that has to be more than 70.
2L + 2W > 70
We know that the length is 19, so 2L = 38.
2W + 38 > 70
2W > 70  38
Now pick a width that makes that true. There are lots of them to choose from: a million will do. :)