How can you prove that the quadrilateral is a rectangle?

Acircle has a circumference of 28.36 units what is the diameter of the circle

The mean finish time was 185.52 with a standard deviation of 0.327 minute. the winning car driven by chris finished in 185.13. the previous year race had a mean finish time of 110.3 with a standard deviation of 0.106. the winning car that year driven by karen finished in 110.13 minutes. find their respective z-scores. chris - z-score karen “- z-score

If np3 /nc2 = 6, find the value of n