A ring wall that is planned for the support of a water storage tank measures 12″ thick, 30″ tall, and has a circumference of 50`. How many cubic yards of concrete are required for this ring wall? (Do not include waste.)

A ring wall that is planned for the support of a water storage tank measures 12″ thick, 30″ tall, and has a circumference of 50`. How many cubic yards of concrete are required for this ring wall? (Do not include waste.)