Does the outer diameter of a concentric circle include the inner diameter? Sorry, stupid question

Question

mathstudent55 · Answer

|dw:1399258590645:dw|

anonymous · Answer

thank you! that's what i was thinking. I have to measure the outer diameter of an image using a program called Image J, and it asked for the outer diameter of the image

anonymous · Answer

I measured from the center to the outskirt of the white image and multiplied by 2

anonymous · Answer

does that seem correct?

mathstudent55 · Answer

Yes, that is the diameter. You can also just measure the diameter directly.

anonymous · Answer

Thank you! The "outer diameter" portion of the question threw me off. I guess they couldn't just ask me to measure the "diameter" because the inner black region forms a circle, which has its own diameter (inner diameter) right?

mathstudent55 · Answer

Correct. There are an outer diameter and an inner diameter.

anonymous · Answer

Thanks so much for your help! :)

mathstudent55 · Answer

You're very welcome.