HELPP ME PLS How could you calculate the x-coordinate of the midpoint of a horizontal segment with endpoints at (0,0) and (20,0)?

Acircular garden with radius of 8 feet is surrounded by a circular path with a width of 3 feet. what is the approximate area of the path alone? use 3.14 for π

If the ratio of sum of the first m and n terms of an ap is m2 : n2 , show that the ratio of its mth and nth terms is (2m − 1) : (2n − 1).

Anyone? 15m is what percent of 60m; 3m; 30m; 1.5 km?