Mathsy question

[Tractor]

cos theta = adj/hypotenuse

=> hypotenuse * sin theta = height
=> 5ft * sin 25(pi/180) = height
=> height = 2.11308989034ft

Incredible. I wish i could understand how you get to that.

[Rupert]

http://www.bbc.co.uk/schools/gcsebitesize/maths/geometry/trigonometryrev1.shtml

GCSE maths

if you put calculator in degrees you don't need to convert to radians. Also top line was wrong formula, lol

[celtic]

cos theta = adj/hypotenuse

=> hypotenuse * sin theta = height
=> 5ft * sin 25(pi/180) = height
=> height = 2.11308989034ft

I make it about the same.

[RED-DOG]

cos theta = adj/hypotenuse

=> hypotenuse * sin theta = height
=> 5ft * sin 25(pi/180) = height
=> height = 2.11308989034ft

I make it about the same.

...and we're back to 5ft planks.

[booder]

cos theta = adj/hypotenuse

=> hypotenuse * sin theta = height
=> 5ft * sin 25(pi/180) = height
=> height = 2.11308989034ft

I make it about the same.

...and we're back to 5ft planks.

Too easy Tom , too easy.

[RED-DOG]

cos theta = adj/hypotenuse

=> hypotenuse * sin theta = height
=> 5ft * sin 25(pi/180) = height
=> height = 2.11308989034ft

I make it about the same.

...and we're back to 5ft planks.

Too easy Tom , too easy.

I know, I feel dirty now.

The closest I could get to working out 25 degrees of elevation was 4in up for every 12in of length.

So 5tft is 5x4in =25in.

If course, as I raise the plank it becomes shorter horizontally so it's just a rough estimate rather than an actual answerer.

I think I'll just lift it up until it looks right.

[EvilPie]

cos theta = adj/hypotenuse

=> hypotenuse * sin theta = height
=> 5ft * sin 25(pi/180) = height
=> height = 2.11308989034ft

Can we, or I suppose the question is should we decimalise an imperial measurement?

2.113ft is pretty meaningless isn't it? Some people could easily mistake this for 2' 11" when it's actually about 2' 1 1/3"

Probably best to convert 5ft in to metric first which won't go down well but it'll give a far more accurate way of getting that vertical height.

[tikay]

cos theta = adj/hypotenuse

=> hypotenuse * sin theta = height
=> 5ft * sin 25(pi/180) = height
=> height = 2.11308989034ft

I make it about the same.

...and we're back to 5ft planks.

Too easy Tom , too easy.

I know, I feel dirty now.

The closest I could get to working out 25 degrees of elevation was 4in up for every 12in of length.

So 5tft is 5x4in =25in.

If course, as I raise the plank it becomes shorter horizontally so it's just a rough estimate rather than an actual answerer.

I think I'll just lift it up until it looks right.

That was always going to be Tom's solution.....