Please help me with math?

Question

If the side e of a square is increased by 1%, then the area is increased approximately 

 

a) 0.02e

b) 0.02e^2

c) 0.01e^2

d) 1%

e) 0.01e 

 

Answer: B

 

Please show all your work. 

Answer 1

A=e²  if we now replace e by 1.01*e (a 1% increase) A is now (1.01e)² =1.021e² so the area has increased by .02e²

so the correct answer is b)

 

Jim

Answer 2

Hi Sun;

100%=1

100%+1%=1.01

first area of a square=(e)(e)=e²

second area of a square=[(1.01)(e)][(1.01)(e)]=1.0201 e²=1.02 e²

 

change of area of square=[(1.02)(e²)]-[(1)(e²)]

change of area of square=0.02 e²

This corresponds to answer B.