Extrude with Offset

Step 1) Create a rectangle centered at the origin with a height of 20 and width of 30:

30by20rectangle

Step 2) add an arc as shown. Make sure it’s dimensioned :

30by20rectanglewarc

Step 3) Now the bottom:

30by20rectanglewarcNumba2

 

Step 4) Extrude the shape by 25MM:

extrude25mm

Step 5)  un-hide sketch 1

unhideSkettch1

Step 6)

Go into sketch 1 and create  2 MM offset on the top arc and on the bottom arc, then connect their endspoints with lines :

offset as 2

Step 7)

Final Result

final-result