Question

What is the exact area of a circle whose diameter is 18 cm?

Answer 1

formula

A = pi*r^2

pi = 3.14 approximately
r = radius = half of diameter

Answer 2

ok so each answer is in terms of pi, so ignore the pi's for now

Answer 3

whats the radius?

Answer 4

18 divided by 2

Answer 5

diameter = 18
radius = half of diameter

Answer 6

so 9

Answer 7

yep

Answer 8

then you plug that into A = pi*r^2

Answer 9

3.14 x 18

Answer 10

\[3.14 \times 8 \times 8 \]

Answer 11

200.96

Answer 12

divide it by 2?

Answer 13

Wait... Let me try this again...

Answer 14

again, ignore the pi's

Answer 15

every answer choice has a pi in it

Answer 16

8x8 = 64

Answer 17

but you found the radius to be 9, not 8

Answer 18

9 x 8 = 72

Answer 19

r^2 means r times r

Answer 20

r = 9

Answer 21

9 x8 x8 ?

Answer 22

576

Answer 23

idk how you're getting 9 x 8

Answer 24

r^2 = r x r = 9 x 9 = ??

I replaced the 'r's with 9 since the radius is 9

Answer 25

81?

Answer 26

yep so 81pi is your answer

Answer 27

Thank you!!!!