If you know the circumference of a circle you can use a revision of the formula for the area of a circle. Area of a circle formula. A Circle area.
C 2 p r.
The diameter of a circle is the length of a straight line drawn between two points on a circle where the line also passes through the centre of a circle or any two points on the circle as long as they are exactly 180 degrees apart. A Circle area. Area A 314 x 2 x 2 4. Area of a Circle Calculator.