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Problem of the Week
Problem A and Solution
Sorting Shapes
Problem
Look at the following shapes. Sort them into the Venn diagram according to the requirements.
Challenge: Can you draw a pentagon, a hexagon, and an octagon that have at least one pair of
parallel lines, and at least one right angle.
Solution
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Teacher’s Notes
There is a debate about the definition of a trapezoid. Some people define a trapezoid as a
quadrilateral with at least one set of parallel lines, and some define it as a quadrilateral with
exactly one set of parallel lines.
With the first definition, a parallelogram, a rectangle, and a square would all be considered
trapezoids. With the second definition, none of those quadrilaterals would be considered
trapezoids.
To add to the confusion, some people in the world use the word trapezium instead of trapezoid.