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## 'Up and Across' printed from http://nrich.maths.org/

The problem provides a visual context in which to consider how
graphs can represent horizontal and vertical movement over time.

A possible start to using the interactivity in a classroom could
involve asking students to sketch the graphs in advance, before
seeing the polygon(s) roll. Their suggestions could be displayed
for all to see and discuss.

The pause button could be used to focus discussion on the different
stages of the "journeys" and to make conjectures about what will
follow.

Possible follow up questions:

- Some graphs start at the origin and others don't. Can you
explain why?

- Some graphs have sections that are horizontal and others don't.
Can you explain why?

- Why is the horizontal speed not constant during each stage of the
"journey"?

This problem is the third of three related problems.

The first two problems are

How far does it move? and

Speeding up, slowing down .