An observation point was originally in line with the top of a waterfall, but the waterfall moves a constant distance each year from erosion. the following graph shows the relationship between the time since 1998 and the distance the top of the waterfall is from the observation point. negative years represent time before 1998

Iwill give ! if m∠a=59 and m∠3=81°, what is m∠b? m∠b= _[blank]_°

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

Thompson and thompson is a steel bolts manufacturing company. their current steel bolts have a mean diameter of 127 millimeters, and a variance of 36. if a random sample of 35 steel bolts is selected, what is the probability that the sample mean would differ from the population mean by greater than 0.5 millimeters? round your answer to four decimal places.