What do builders use trigonometry for?

Answer 1

I am a builder and I may use trigonomtry for figuring out the length of the sloping part of a roof without having to climb up and physically measuring it. This requires that you know the roof angle. Which if you can't read it out of the drawing plans you can sometimes measure inside the house or as a last resort climb up and measure the actual angle. The length of the roof equals half the breadth of the house divided by cosinus to the roof angle.

Another instance where trigonometry comes in handy is when you wish to determine if you have managed to mark the rectangular shape of the foundation correctly. That is you want to know if the angles are all straight (90 degrees). If the two diagonals are the same, you are in business. The sides must be correctly measured too of course...

A third instance is when you wish to create a right angle. I then use a 3-4-5 triangle. The angle between the 3 and 4 sides is always 90 degrees. You may use yards, meters or whatever unit you wish of course the ratio is what counts.

Constructing complcated roofs calls for more trigonometry, but I venture to say that the examples above are the most common uses of trigonometry in building houses.