(6) find the fourth angle of the quadrilateralwhose three angle are 106 , 85 ,34​

Let the measure of the fourth angle be x°.

We know that the sum of the angles of a quadrilateral is 360°.

Therefore, 54 + 80 + 116 + x = 360

⇒ 250 + x = 360

⇒ x = (360 - 250) = 110.

Hence, the measure of the fourth angle is 110°.