What equation represents a circle with its centre at the origin, and a radius measuring 12 units

I’m stuck on this i don’t understand.

The equation of a circle is (x - 3)2 + (y - 7)2 = 25. determine the length of the radius. 4 25 12.5 5 write the standard equation of the circle with center (2, 3) and a diameter of 12. (x - 2)2 + (y - 3)2 = 36 (x + 2)2 + (y + 3)2 = 12 (x - 2)2 + (y - 3)2 = 6 (x - 3)2 + (y - 2)2 = 36 the equation of a circle is (x + 3)2 + (y + 7)2 = 25. where is (3, 4) located in relation to the circle? on the circle in the interior of the circle in the exterior of the circle at the center of the circle

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.