Since Dave and Mary are going opposite directions every hour mary will be moving 50 miles away and Dave will be moving 40 miles away meaning they will move 90 miles away from each other every hour. So 270 is 90 times three so in three hours they will be 270 miles away so at 1 pm they will be 270 miles apart.
The formula for the circumference of a circle is 3,14 (pi) x diameter. We know that the radius is half of the diameter so therefore you do 16x2= 32 —> 3,14x32= 100,48mm. Answer: 100.48mm
