# Math Help - area and circumference

1. ## area and circumference

Hi all,
i am not able to get the relation between area and circumference in the given below.could any one please help me out

If the circumference of a circle is decreased by 50% then the percentage of decrease in its area is?

Regards

2. Circumference = 2*pi*r which can be rewritten as r= C/(2*pi)
Area = pi*(r^2)
substitute with 50% of C
pi * ((1/2)(1/(2*pi))^2

Hi all,
i am not able to get the relation between area and circumference in the given below.could any one please help me out

If the circumference of a circle is decreased by 50% then the percentage of decrease in its area is?

Regards
If you magnify the length of a shape by a scale factor $k$, then the area is magnified by $k^2$.
In this case, the length scale factor $k = \frac{1}{2}$.