20 can be divided by 2 twice, with 5 remaining
20 can be divided by 4 once, with 5 remaining
20 can be divided by 5 once, with 4 remaining
20 can be divided by 10 twice
20 can be divided by 20 once
hope this helps
The answer to one would be 25534
The area of the rectangle should be 87.1cm^2