Question 36657
100*120=12,000 SQUARE FEET FOR THE ENTIRE LAWN 1/3*12,000=4000 SQUARE FEET MOWED USING THE OUTER EDGE.

THE RATIO OF THE LAWN MEASUREMENTS IS 10/12 SO THE RAMAINING RECTANGLE MUST ALSO BE A 10/12 RATIO THUS 10X*12X=8000 OR 120X~2=8000 OR X~2=8000/120 OR 66 2/3 OR X=8.165 THUS THE CENTER 2/3 IS 10*8.165=81.65 FEET & 12*8.165=97.98 FEET.

PROOF 81.165*97.98=8000 OR 8000=8000