# Homework Help: Hi from Spain, help me with object size and distance. please.

1. Sep 1, 2009

### reservahoy

1. The problem statement, all variables and given/known data

Thank you very much in advance if you help me to resolve this problem. I am 3D designer and I must to defend that the object is visible from the beach but so small. sorry my english!
Please if you can contribute with formulas and solve the problem will be valued, because I would like to resolve by myself with differents parameters.

Problem:
I have an object of 80 meters of height and 5 meters of diameter.
This object is above the sea and 9000 meters far from the beach.
The object is like a wind generator white.

Questions:
1. its visible the object from the beach?
2. what height has the object from the beach?
3. what distance I need to see the object?

2. Relevant equations

3. The attempt at a solution

2. Sep 1, 2009

### kyiydnlm

try perspective projection.

3. Sep 1, 2009

### reservahoy

Thank you for your answer. I tried to find information about perspective projection and I think that isn't that I looking for.

I need to explain the information like this:

the object seen to 9000 meters of distance has 3mm of height. Why? because the formula to calculate this results is x+y=z , where x is distance, y is height, etc, (this is a sample formulas and number are not real)