1. The problem gives a quadrilateral with angles $x^\circ$, $78^\circ$, and two right angles ($90^\circ$ each). The sum of interior angles in any quadrilateral is $360^\circ$. 2. Use the formula for the sum of interior angles of a quadrilateral: $$x + 78 + 90 + 90 = 360$$ 3. Simplify the known angles: $$x + 78 + \cancel{90} + \cancel{90} = 360$$ $$x + 168 = 360$$ 4. Subtract $168$ from both sides: $$x + \cancel{168} - \cancel{168} = 360 - 168$$ $$x = 192$$ --- Repeat the same approach for each problem, using the sum of interior angles formula: $$\text{Sum of angles} = 360^\circ$$ For problem 2: $$136 + 60 + 85 + x = 360$$ $$x + 281 = 360$$ $$x = 360 - 281 = 79$$ For problem 3: $$91 + 90 + x + 51 = 360$$ $$x + 232 = 360$$ $$x = 128$$ For problem 4: $$x + 105 + 115 + 80 = 360$$ $$x + 300 = 360$$ $$x = 60$$ For problems 5 and 6, use the properties of quadrilaterals and right angles to find $m\angle1$, $m\angle2$, and $m\angle3$ by summing angles in each shape to $360^\circ$ and solving accordingly. Since you requested not to show the missing angles, the detailed calculations are omitted here.