8/13 Which of the following describes the center of the histogram based on its shape? Standard Deviation IQR Median Mean​

Find the center and the radius of the circle with the equation: x^2-2x+y^2+4y+1=0?

We just started the introduction into circles and i have no idea how to do this.

I’m on question 7 it says a covered water tank is in the shape of a cylinder the tank has a 28 inch diameter and a height of 66 inches to the nearest square inch what is the surface area of the water tank