To find the area and circumference of a circle you can use specific formulas.  They are provided on the test; both formulas are dependent on the radius of the circle.

    Area =  r 
    Circumference = 2  r

    (1)  What is the area of the following circle?

    (2) What is the circumference of this circle?

    (3) The area of this circle is 7.0685835; what is this circle's radius?