Question

if the circumference of a circle is increased from 4pie to 8pie then find the percentage increase in the area of the circle​

Answer 1

Answer:

300 %

Step-by-step explanation:

If circumference = 4 pi

then ,

radius = r

c =2*pi*r

4×3.14= 2×3.14×r

12.56=6.28×r

12.56÷6.28 =r

hence , r =2

therefore, when c = 8 pi , r = 4

AREAS

when r = 2 ,

a = pi×r×r

a = 3.14 ×2×2

a=3.14 ×4

a= 12.56 units sq.

when r =4 ,

a=pi×r×r

a=3.14 ×4×4

a=3.14×16

a=50.24 units sq.

Increase in area =50.24 - 12.56

=37.68

% increase = increase/original ×100

=37.68/12.56 ×100

=3 × 100

= 300

Hence , the area increased by 300 %.