hello: Increase in length is : (30×10)/100 =3 cm Increase in width is : (20×5)/100 = 1 cm the new length is : 30 cm+3cm =33 cm the new width is : 20cm+1 cm =21 cm the perimeter is : 2(20+30) = 100 cm the new perimeter is : 2(33+21) = 108 cm the pourcentage increase in the perimetr is : 8% 108 =100/100+8/100=1+8/100
