SUNDAY PUZZLE #48
If a line is drawn from the top of each cactus (175 cm and 70 cm) to the bottom of the other, as shown in the diagram, they intersect at a point 50 cm above the ground. What is the distance between the cacti (PQ)?
The height of the point of intersection of the above mentioned lines depends only on the heights of the two cacti and is independent of the distance between the two cacti.
You can move the points P and Q in the figure to see for your self.

You can move the points P and Q in the figure to see that the height of the point of intersection remains the same.