The missing side length should be 22. Add 13.5 to 14.5 and you should get 28. Subtract 28 from the total perimeter (50) to get 22.
Put a picture so we can see
Answer:
we express the ratio of pencil to eraser and multiply it by the number of the number of pencils and erasers. 4/5 * x=20 , so x=25, then it implies that there are 5 erasers.
1:10 or 100:1000 so the point is to just add one zero to each side and you'll get it right
