First we have to find the diameter the find the radius. We already know that the circumference is 31.4 what we have to do now is work backwards. ( 31.4 / 3.14=10) If the diameter of a circle is 10 the radius is 5. now we just have to follow πr"2" to find the area of a circle. (5"2"= 25 x 3.14= 78.5 units)