If the radius of the circle increases by 10%, what is the percentage of area? Expres the solution.

Question

anonymous · Answer

first we gotta know the formula: (final-intital)/intial*100%= percent change

the final value we plug in r=1.1, so the final area is 2*pi*1.1
the initial value we plug in r=1, so the initial area is 2*pi
and then according to the formula, we find the percent change =10%(look so weird to me tho)

anonymous · Answer

the answer is 21%

anonymous · Answer

I know what I did wrong... pls follow ujge321 ...... I find the circumference...... it is 21%

anonymous · Answer

yeah 21%

anonymous · Answer

cluimay9 u calculated the circumference of the circle

$$2 \pi r$$
but area is $$\pi r^2$$

anonymous · Answer

I knew it^^ the first time i was doing with 2pir but for somereason i thought this is volume.....

anonymous · Answer

a circle is a 2D structure so it cannot have volume but it resembles a sphere in 3D and a sphere has a volume

anonymous · Answer

cliumay9, can you write down how you got 21?