If the ratio of sides is 3/4, the ratio of areas is (3/4)² = 9/16.
The area of the smaller polygon is (9/16)*(320 m²) = 180 m².
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"Regular" is not a sufficient descriptor to guarantee the polygons are similar. A quadrilateral and a hexagon can both be regular polygons, but their areas will have quite a different ratio from that assumed above. We assume the polygons are similar.
