Question

The sides of a rectangle are 40 cm by 30 cm if each increase by 10 % find the percentage increase in area

Answer 1

Answer:

$21\%$

Step-by-step explanation:

$Original \: \: area= L \times B= 40 \times 30=1200cm^2 \\ </p><p>New \: length \: of \: the \: 40cm \: side=40+ \frac{10}{100} \times 40 \\ = 40 + 4 = 44 \\ New \: length \: of \: the \: 30cm \: side = 30 + \frac{10}{100} \times 30 \\ = 30 + 3 = 33 \\ thus \: the \: \: new \: area \: is - \\ 33 \times 44 = 1452cm {}^{2} \\ ths \: percentge \: increase \: is - \\ \frac{1452 - 1200}{1200} \times 100 = 21\%$

Answer 2

Answer:

21%

Step-by-step explanation:

Originalarea=L×B=40×30=1200cm2Newlengthofthe40cmside=40+10010×40=40+4=44Newlengthofthe30cmside=30+10010×30=30+3=33thusthenewareais−33×44=1452cm2thspercentgeincreaseis−12001452−1200×100=21%