According to the statement the smallest angle of triangle =
2
3
of the smallest angle of the quadrilateral. ∠A =
2
3
×3x = 2x Largest angle = 2 (smallest angle of the triangle)
∠B = 2(2x) ∠B = 4x
Now ∠C = 180° − (2x + 4x) ∠C = 180° − 6x Sum of the second largest angle of the triangle + largest angle of the quadrilateral = 180° − 6x + 6x = 180°