For example, you could take the barometer out on a sunny day and measure the height of the barometer and the length of its shadow, and the length of the shadow of the building and by the use of a simple proportion, determine the height of the building."
(you; could take out; T:on a sunny day) (you; measure; the height of the barometer)
you you
could take out measure
T:on a sunny day
the height of the barometer