Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ ¹ ² ³ °
 

You are not logged in. #1 20111219 02:14:39
3dimentionWhat is the angle between two adjacent plans of a equilateral triangular pyramid of length 'a' and the perpendicular height of the pyramid is 'h'? Last edited by Psalmycole (20111219 02:49:36) #2 20111219 02:26:04
Re: 3dimentionI need a simplified formular for this. If not so explain how i can do it. Last edited by Psalmycole (20111219 02:33:39) #3 20111219 03:19:36
Re: 3dimentionhi Psalmycole (iii) Find point G on VB so that CGV = 90 Second diagram shows true shape of VBC (iv) The required angle is AGC AG = GC AC = a Bob Last edited by bob bundy (20111219 19:57:53) You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei #4 20111221 01:39:37
Re: 3dimentionHi bob? I did follow your work. The last part is like ok, but how u came to get GC, i didn't get it. #5 20111221 01:48:19
Re: 3dimentionCan you prove me right or wrong when i say: cosAGC 16h^22a^2)dvide by (a^2) #6 20111221 05:14:25
Re: 3dimentionhi Psalmycole My expression is much more complicated. Using your formula and with a = 4 and h = 3.265986 (which will make a regular pyramid = tetrahedron ) I got cos AGC = 5.9375 which is not possible! I used my formulas and got angle = 70.528779 which is the Wiki value. How did you get your expression? I'll check your working. Bob Last edited by bob bundy (20111221 05:44:16) You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei #8 20111225 22:40:48
Re: 3dimentionhi, #9 20111226 05:46:48
Re: 3dimentionhi arieneytio So the angle netween a sloping side and the base is I was trying to calculate the angle between two sloping sides. Bob Last edited by bob bundy (20111226 19:42:54) You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei 