Triangle with parameters : angle a, radius r, radius r
    

Construction :

      1. Central angle BOC, |angle BOC| = 2a (|BO| = |CO| = r).
      2. Line p || BC in length r from BC appropriate halfplain whiped by line BC.
      3. Circle l = (O;).
      4. k Ç p = S.
      5. Circle l = (S; r.
      6. Strings q1, q2 to circle l, B Î q1, C Î q2
      7. q 1 Ç q2 = A.

Conditions of solvability :

  (r ³ 2r) /\ (r cos a + ³ r.

Number of solutions :

  1. if r cos a + = r
  2. if r cos a + > r