## stupidinmath one year ago what is the circumference of the circle x^2+y^2-10y-36=0? a. 38 b. 49 c. 54 d. 125 e. 192

1. eliassaab

$x^2+y^2-10y-36=0\\ x^2+y^2-10y+25 -25-36=0\\ x^2 +(y-5)^2 = 61=r^2\\ r=\sqrt{61}\\$

2. eliassaab

$2 \pi r = 2 \pi \sqrt{61}=49.0732$

3. eliassaab

It seems b is the answer

4. jmiller22

Yes it is B.49

5. stupidinmath

oh, thanks!