What is the circumference of the circle whose equation is (x - 9)2 + (y - 3)2 = 64?

8p
64p
16p
4p

Question

What is the circumference of the circle whose equation is (x - 9)2 + (y - 3)2 = 64?
 	
	8p
	64p
	16p
	4p

stamp · Answer

Circumference is defined as C = 2pi r 

The missing piece is knowing the radius.

Can you determine the radius of our circle in question? Perhaps you can find the r value from the circle equation.

Once you know the radius, you can substitute the radius r into your C = 2pi r and determine your circumference

anonymous · Answer

i have no clue on how to find the radius

stamp · Answer

This is the general form of a circle equation$$(x-a)^2 + (y-b)^2 = r^2$$

anonymous · Answer

ohh so its 8p?

stamp · Answer

$$r^2=64$$so$$r=8$$

If C = 2pi r, and r = 8

What is C?

anonymous · Answer

16?