TRIA(<real expression>, <real expression>, <real expression> / <,stream> /);Returns a REAL value of a random variable whose probability function is a triangular function with minimum equal to the first <real expression>, mode equal to the second <real expression>, and maximum equal to the third <real expression>, computed with random numbers taken from the stream indicated by <stream>. This is an integer from 1 to 10. If omitted, 1 is assumed.