Answer:
13
Step-by-step explanation:
since the inside of a triangle is equal to 180
180-42-73=65
65/5=13 so 13 should be the answer.
Sum of the interior angles of a triangle= 180°
Therefore, 42°+ 73°+5a= 180°
=> 115°+5a = 180°
=> 5a= 180- 115°
=> 5a = 65°
=> a = 65°/5
=> a= 13°
