Question

WHAT IS THE AREA OF A CIRCLE WITH THE CIRCUMFERENCE OF 31.4CM?

Answer 1

Think about it. Whats the formula for circumference?

Answer 2

\[circumference = 2 \pi r\]find r
then \[area = \pi r^2\]

Answer 3

for finding area we need value of radius ....
circumference = 2πr
Area = πr^2

Answer 4

31.4CM =2πr
r = 4.99

Answer 5

Get it? Cuz 31.4CM divided by 2 divided by π gives you r

Answer 6

Round that number to 5.

Answer 7

Now plug the new radius into the area formula

Answer 8

πr2

Answer 9

π5^2

Answer 10

= 78.5cm3

Answer 11

pottersheep has just established that:\[\text{area of a circle}=\frac{c^2}{4 \pi }\]