Denoting three angles A, B, and C does not distinctively define a triangle, but any two triangles with the same angles are alike. While, specifying two angles of a triangle gives the third angle automatically, since the sum of angles in a triangle equals 18 degrees.
Find angle C from angle A=5o and angle B=7o
angle A = 5o angle B = 7o
Substitute the given values in the respective formula,
C = 18o - 5o - 7o C = 18o - 5o - 7o C = 6o