first you have to divided 31.4 by 3.14 to get your diameter so you can get your radius. 31.4 divided by 3.14 equals 10 and 10 divided by 2 equals 5 which is you radius. The formula for area for a circle is πr². 5 squared is 25 and 3.14 times 25 equals 78 .54 which is your answer.
