Problema Solution
The sides of a rectangle are 20 cm and 15 cm .if each side of the rectangle is increased by 20 %,find the percentage increase in the area.
Answer provided by our tutors
Solution:
Original area:
A1 = 20(15) = 300cm2
New area:
A2 = (20*1.2)(15*1.2) = 432cm2
% increase = (432 - 300)/300 x 100%
% increase = 44%
just want to ask how does 1.2 come in A2 please help me i'm not getting it.
Answer provided by our tutors
the area of the original rectangle is:
A1 = 20*15 = 300 cm^2
the original length is 20 cm and is increased by 20%
the new length is:
20 + 20*(20/100) = 20 + 20*0.2 = 20(1 + 0.2) = 20*1.2
the same with the 15 cm width that is increased by 20%
the new width will be:
15 + 15*(20/100) = 15 + 15*0.20 = 15(1 + 0.20) = 15*1.2
thus the new area will be:
A2 = (20*1.2)(15*1.2) = 432
% increase = ((432 - 300)/300) x 100%
% increase = 44%