Question

if radius of a circle decreases by 20% find the percentage change in area of a circle​

Answer 1

Answer:

question is wrong bro.......

Answer 2

Answer:

here radius of a circle decrease by 20 percent

To find :-

area of circle

new radius is 80 percent after decrease the old radius 20 percent

New radius = 80 percent

r = 0.8 r

$area \: of \: circle \: = \pi {r}^{2} = a1$

$new \: area \: of \: circle \: = \pi(0.8) {}^{2} = a2$

The decreasing change in radius :-

$\frac{a1 - a2}{2} \times 100$

$\frac{\pi {r}^{2} - \pi {(0.8)}^{2} }{2} \times 100$

$\frac{r {}^{2} - \: 0.64 {r}^{2} }{2} \times 100$

( 1 - 0.64 ) × 100

0.36 × 100

= 36 %

This is your answer....

Thanks....