Solve the triangle please! A=13 yards b=9 yards c=5 yards?

 I hope you meant: a = 13 yards ... (and not A = 13 degrees)

  side a = 13 yds: → is opposite angle A

  side b = 09 yds: → is opposite angle B

  side c = 05 yds: → is opposite angle C

 Use the Law of Cosines:

     c² = a² + b² − 2 • a • b • cos[C]

   (5)² = (13)² + (9)² − 2 • (13) • (9) • cos[C]

  cos[C] = 0.96154

       C = 15.94 → 16 degrees

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again:

      a² = b² + c² − 2 • b • c • cos[A]

   (13)² = (9)² + (5)² − 2 • (9) • (5) • cos[A]

   cos[A] = - 0.7

        A = 134.427 → 134 degrees

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  angles: B = 180 − (A + C)

         B = 180 − (134 + 16)

         B = 30 degrees