To get the maximum distance, you first use the given numbers as
basis.
10 meters/3 meters =x/4.5 meters
Where x = the maximum distance the projector can be placed that
can produce an image 4.5 meters high
3x = 10 (4.5)
3x = 45
X= 45/3
X= 15 meters
So, the maximum distance
that the projector can be placed from the screen which produces an image
4.5 meters high is 15 meters.
