This problem in geometry has been solved in no less than EIGHT ways
by a pair of students. How would you solve it? How many of their
solutions can you follow? How are they the same or different? Which
do you like best?
Stage: 4 Challenge Level:
This image (not to scale) represents the positions of the Earth,
moon and sun in a solar eclipse.
Which lengths on the diagram do you know?
How can you use this to work out the apparent size of the moon and
The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the
NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to
embed rich mathematical tasks into everyday classroom practice. More information on many of our other activities
can be found here.