It is centered at (h,k) --> (0,0) and has a radius 9
The equation of the circle is

Hope that helps!
64÷2 =32
90-32=58
58+58=116
360-116=244
?=244°
Answer: 16 units
Step-by-step explanation: adding the perimeter sides to get the perimeter of triangle ABC would be 4.1+6.1+5.8 = 16