1. The problem statement, all variables and given/known data Find the equation of a circle if the circumference is 18∏ and contains the point (2, 8) 3. The attempt at a solution I know I can find the radius by setting 18∏=2∏r. r=9. the equation of a circle is (x-h)2+(y-k)2=r2 So I have 92= (2-h)2+(8-k)2 which becomes 81= 4-4h+h2+64-16k+k2 I can simplify this down to -4h + h2 +68 -16k +k2 = 81 To my understanding, containing the point does not mean the center, but on the circumference of the circle. I'm lost.