Why must eye protection be worn at all times in welding shop?

Which is an equation of a circle with center (2, 7) and radius 4? (x - 7)2 + (y - 2)2 = 16 (x - 2)2 + (y - 7)2 = 4 (x – 2)2 + (y - 7)2 = 16 (x + 2)2 + (y + 7)2 = 4