What is the circumference of the circle? (x+4)^2+(y-5)^2=81

My math teacher told my class to "steal" a 6th grade fraction word problem from the internet, word problems? : -p requirements: only a 1 step word problem. needs to be complex.

Which of the following circles have their centers on the x-axis? check all that apply.

Simplify the rational expression. state any restrictions on the variable. t^2-4t-12 / t-8 the / is a fraction sign.