Curved surface area of half cylinder

In the figure shown below, m < 40 and ab =8. which equation could be used to find x?

Abacteria population is tripling every hour. by what factor does the population change in 1/2 hour? select all that apply

Apassenger train and a freight train leave san jose at 3pm, traveling in the same direction. the passenger train is going three times as fast as the freight train. at 6pm they are 240 miles apart. how fast is each travelling? explain your answer and show your