### Video Transcript

Half the circumference of a certain circle is 392.5 centimetres. Determine its diameter, using 3.14 in place of π.

The question is asking us to determine the diameter of this circle. The diameter of a given circle is two times its radius. Since the radius of this circle is not given, we will have to calculate, using the formula circumference over two times π. The circumference of the circle isnβt given. But we are told that half of the circumference is 392.5 centimetres. So to calculate the circumference, we need to multiply this number by two, which equals 785 centimetres.

Now, we can calculate the radius by dividing 785, the circumference, by two times π. The question tells us to use 3.14 in place of π. So in this question, two times π is 6.28. Now, we can calculate 785 divided by 6.28 on a calculator. So the radius of our circle is 125 centimetres. But the question has asked us to find its diameter. So we need to multiply this number by two. 125 multiplied by two is 250.

So the diameter of this circle is 250 centimetres.