Solve this exercise

Step 1: Identify the given angle and its relationship with angle $a$. The angle given as $120^\circ$ is in the position of angle $d$. Angles $a$ and $d$ are adjacent angles on a straight line, so their sum is $180^\circ$. $a + d = 180^\circ$ $a + 120^\circ = 180^\circ$

Step 2: Calculate the value of $a$. $a = 180^\circ - 120^\circ$ $a = 60^\circ$

Step 3: Identify the relationship between angle $b$ and angle $d$. Angles $b$ and $d$ are vertically opposite angles. Vertically opposite angles are equal. $b = d$ $b = 120^\circ$

Step 4: Identify the relationship between angle $c$ and angle $a$. Angles $c$ and $a$ are vertically opposite angles. Vertically opposite angles are equal. $c = a$ $c = 60^\circ$

The values are: a = \text{60^\circ} b = \text{120^\circ} c = \text{60^\circ} d = \text{120^\circ}

Drop the next question.