What is the measure of angle x

Ricardo ran the 400 meter race 3 times his fastest time was 54.3 seconds his slowest time was 56.1 seconds if his average time was 55.0 seconds what was his time for the third race

Find the number of positive three-digit even integers whose digits are among 9, 8, 7,5, 3, and 1.

Acircle has a radius of 5/6 units and is centered at (3.6, 7.8) write the equation of this circle