Stage: 5 Challenge Level:
Why do this
The problem involves simple geometrical reasoning, calculating with
ratio and proportion, and solving quadratic equations. It requires
a decision to divide the sides of triangle PQR in the same ratio
because otherwise there would be too many variables to work with.
Discussion of the choices to be made in order to solve this problem
provides good experience of how to set about mathematical
How can we express the area of triangle ABC in terms of the area of
triangle PQR so that only one variable is involved?
What can we deduce if we know that one are is a certain fraction of
the other area?