The length is twice the width. Draw a bar model to see the perimeter units.<br><br>[[model:questions/solutions/q7548.png]]<br><br>&bull; Let width = 1 unit, length = 2 units<br>&bull; Perimeter = 2 × (length + width) = 2 × (2 units + 1 unit) = 2 × 3 units = 6 units<br>&bull; 6 units → 42 cm → 1 unit → 42 ÷ 6 = 7 cm<br>&bull; Width = 7 cm, Length = 2 × 7 = 14 cm<br>&bull; Area = length × width = 14 × 7 = 98 cm&sup2;<br><br>The length is 14 cm and the area is 98 cm&sup2;.<br>Check: Perimeter = 2×(14+7) = 2×21 = 42. ✓