w/robe Posted October 1, 2015 Share Posted October 1, 2015 It is over 30 years since I took a maths exam and since then my trigonometry knowledge has leaked out of my brain. I could ask my son this question, as he is taking Maths and Further Maths A levels, but it would be really useful to know today where the crinoline hoop will sit on the panels of our panto dames walk-down dress. So, here goes... A right angle triangle opposite 151mm, adjacent 720mm. If you shortened the same triangle so that the opposite side is 136mm what will the length of the adjacent side be? And in both cases what will the hypotenuse be. Yes I know I can find that with the help of Mr. Pythagoras and so I can work it out for myself if I have to. You do not get extra marks for showing your working. Link to comment Share on other sites More sharing options...
GridGirl Posted October 1, 2015 Share Posted October 1, 2015 Online trigonometry calculator to the rescue! It appears that in your first case, the hypotenuse would be 736mm (rounded up to the nearest mm). In your second case, the adjacent would be 649mm and the hypotenuse 663mm. That seems about right - no doubt someone will correct me if I'm wrong... Link to comment Share on other sites More sharing options...
w/robe Posted October 1, 2015 Author Share Posted October 1, 2015 Thanks GridGirl. So the hoop sits about 3" above the hem, perfect. Link to comment Share on other sites More sharing options...
Jevans Posted October 1, 2015 Share Posted October 1, 2015 GridGirl's numbers are correct (though I did get closer to 648 than 649mm on rounding). Link to comment Share on other sites More sharing options...
w/robe Posted October 1, 2015 Author Share Posted October 1, 2015 GridGirl's numbers are correct (though I did get closer to 648 than 649mm on rounding). My costume making is not as accurate as you give me credit for. One of the pains/pleasures of working in fabric is that it can shift and grow a bit as you work. Link to comment Share on other sites More sharing options...
beware Posted October 1, 2015 Share Posted October 1, 2015 That's not trig. That's similar triangles and ratios... Link to comment Share on other sites More sharing options...
alistermorton Posted October 1, 2015 Share Posted October 1, 2015 And Pythagoras'. But definitely not trig. Link to comment Share on other sites More sharing options...
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