The right figure below is a cross-section of a machine part drawn on a scale of 1:20. What is the actual area of the cross-section? Matter cm

The right figure below is a cross-section of a machine part drawn on a scale of 1:20. What is the actual area of the cross-section? Matter cm

1: 20? What's the unit?
If it's cm, it means that 1cm in the figure is the actual 20cm, and then we can see what shape the section is
Just calculate