Hi nbdesign I will try to give you a few options you can use to get your file to the proper scale. As SketchUp3d_de has explained, the pdf most likely was not at a scale when exported to dwg therefore not coming in correctly. When this dwg is import into LayOut it is placed into a Scaled drawing at a scale to fit your current paper size. The scale of this Scaled drawing (if the original file was to a scale) can changed based on your needs. In your case the scale is incorrect.
Option 1: Scale within LayOut
Ideally you would have something in your drawing that you can base the scale (dimensioned wall, door width, etc…) and I will state that I know LO is not the best tool to scale an object.
In this example I brought in a file and the scale is wrong, I know that this should be 4’
So currently at 1/4"=1’-0" it is reading 3’-7"
In LayOut select Scaled Drawing then Make Scaled Drawing.
Choose a scale 1/4"=1’-0"
Invoke the Line tool and draw a 4’ line or other shape that you will use as a reference.
Press esc to close the Scaled drawing
Now move this entity to the area you want to use as a reference.
Select your imported geometry, Rt click and select Remove Scale (notice dimension now reads 57/64")
Drag the precision gizmo from the center of the selection to the starting point of one edge or your object.
Selecting the corner grip drag and while holding down the Shift+Alt (win) or Shift+Cmd (Mac) to proportionally scale about the center. (dimension now reads 1")
Rt click on the select Group and select 1/4"=1’-0"
Option2: Scale within SketchUp
If your file contains text or dimensions than this option may not be the best as they will be lost when they come into SketchUp
Import the dwg into SketchUp
Invoke the Tape measure tool
On an object you know the scale give it the start and end point then type in the known value. Select ok to scale the model.
Save and Send to LayOut.