The following puzzle will allow you to fill in the blanks.
Imagine (or take) a sheet of A4 (European) paper. The size of the paper is not important but its aspect ratio is. Let the length of the shorter side equal 1 unit. Fold the paper along a line that runs from the corner at a 45 degree angle, resulting in a trapezium shape comprised of a right-angled triangle and a rectangle (i.e. line the shorter side up perfectly with the longer side).
REMEMBER: Treat the shorter length of the unfolded paper as being 1; all other lengths are in relation to this.
Find the perimeter of this new shape to 3 significant figures and then afterwards remove the decimal point to get a 3-digit number. Add 64 to this number. This gives you the digits for the first 3 blanks.
Then find the area of this shape to 3 significant figures. Ignore the preceeding 0 and decimal point to get a 3-digit number. Subtract 287 to get the digits for the final 3 blanks.
You can check your answer at: Geochecker