Circumference and Diameter

Which of these graphs could be the graph showing the circumference of a circle in terms of its diameter ?

Age

11 to 14

Challenge level

Exploring and noticing Working systematically Conjecturing and generalising Visualising and representing Reasoning, convincing and proving

Being curious Being resourceful Being resilient Being collaborative

Problem

Which of the following could be the graph showing the circumference C of a circle in terms of its diameter d?

If you liked this question, here is an NRICH task which challenges you to use similar mathematical ideas.