What is 13 inches equal to in feet

The american academy of pediatrics wants to conduct a survey of recently graduated family practitioners to assess why they did not choose pediatrics for their specialization. provide a definition of the population, suggest a sampling frame, and indicate the appropriate sampling unit.

Acircle has a circumference of 7.850 units. what is its radius?

Is experimental probibilty the same as the observed frequency in math? i need the answer asap!