 Subject Re: Solve Oblique Triangle From Norman Snowden Date Mon, 08 Apr 2019 13:50:04 -0400 Newsgroups dbase.getting-started Thanks Mervyn, you solved the problem! Mervyn Bick Wrote: > On 2019-04-08 6:19 AM, Norman Snowden wrote: > > I realize this is not a normal subject and a Post should not be necessary. However, any comment would be appreciated. Thanks, Norman Snowden > > > > Solve Oblique Triangle. Clockwise start at A to C to B > > > > Without an actual picture please follow this description: > > > >  From A, extend a line due north for a distance of 20 feet to Point C > >  From C, extend a line at North 85.24 degrees West for an unknown distance toward point B > >  From A, extend a line at North 45 degrees West an unknown distance toward B to intercept the line from C to B. > > > > The angle at A is 45 degrees and the angle at point C is 94.76 degrees. > > The angle at point B is 180 – (45 + 9 4.76) = 40.23 degrees > > > > The distance B to C is a  which is opposite A > > The distance A to B is c which is opposite C > > The distance A to C is b which is opposite A and is known as 20 feet. > > > >  From the Law of Sines with b = 20 > > 20/sinB = c/sinC = a/sinA > > > > c = (20 *sinB)/sin C       a = (20 *sinB)/sinA > > c = 12.96 feet  and  a = 18.27 feet > > Here's the problem. > >    c = (20/sinB)*sinC >    a = (20/sinB)*sinA > > > >   > > These values are wrong.  When the triangle is drawn to scale  c  = +- 35 feet and a = +- 25 feet. > > > > This could be solved using Slope Intercept Equations but that should not be necessary. > > > > The triangle meets the Law of Sines requirements and the solution should be simple. > > The SIN() function in dBASE requires its argument to be in radians.  The > dBASE function DTOR() will convert degrees to radians. > > ***** > b = 20 > aA = 45 > aC = 180 - 85.24 > aB = 180 - (aA + aC) > > c = b/sin(dtor(aB))*sin(dtor(aC)) > a  = b/sin(dtor(aB))*sin(dtor(aA)) > > ?'aA = '+aA > ?'aB = '+aB > ?'aC = '+aC > ? > ? 'a = '+a > ? 'b = '+b > ? 'c = '+c > ******** > > This gives the following output > > aA = 45 > aB = 40.24 > aC = 94.76 > > a = 21.89 > b = 20 > c = 30.85 > > > Mervyn. > > > >