We have done some questions like this before, but I can't do this one Jackie is walking towards a tower. At one point she measures the |
The first thing to do is a sketch diagram showing all the measurements you are given in the question.
The height of the tower we have called h, and
the distance from the foot of the tower to the nearer measurement is x.
Looking at the red triangle,
and similarly for the blue triangle,
We must use these two equations to eliminate x and to find the value of h.
Rearranging the first equation to make x the subject gives
and the second equation gives
Now substitute for x into the second equation and rearrange:
The height of the tower works out to be 42.95 metres (to 4 significant figures).