During the third hour after midnight the hands on a clock point in the same direction (so one hand is over the top of the other). At what time, to the nearest second, does this happen?
How many times in twelve hours do the hands of a clock form a right
angle? Use the interactivity to check your answers.
Overlapping Squares
Age 7 to 11 Challenge Level
Describe what is happening in these pictures.
Do the pictures appear to be coming
towards you, or going away?
How many squares are there in each picture?
If the side of the smallest square is 1
unit, how many units is the side of the next square?
And the next?
How many units is the side of the largest
square?
What is the area of the smallest
square?
What is the area of the next square? And
the next?
What is the sequence of the areas of the
squares?
The smallest square is one unit of area. How many more units are in
the second square?
How many more units of area are in the
third square than in the second square?
What is the rule for building the
squares?
Look at the top picture. Start from the largest square and think of
it as shrinking as it turns.
Through what angle has it turned when it
has changed to the smallest square?
Is it the same in both pictures?
What is the angle of rotation as one
square changes to the next?
Is it the same in both pictures?
Make a similar picture. You could change
the rules if you would like to.
This
image, along with the questions and notes, features on the
Exploring Squares CD-ROM, developed by members of the NRICH Team
and published by Virtual Image Publishing Ltd. For more details,
please see ourpublications page.