We just bought an instrument that allows us to take height measurements. The problem is that to be able to take a height measurement, you need to point the laser at the base (m1) of the object and then at the top (m2) (see image, object A) to get h1.
We want to be able to measure height of objects for which we don't see the base (image, object B).
Is it possible using trigonometry to retrieve the height of the object B?
Position yourself as in the following picture.
Then $h_2$ can be calculated by the intercept theorem: $$h_2=h_1 \frac{l_2}{l_1} .$$
Thus the total height of the second building is given by $$ h_0+h_1\frac{l_2}{l_1}.$$