The exterior angle in this problem is 63 degrees.
Relationship between interior angle and two exterior angles of a triangle
In any triangle, the relationship between an interior angle and its two corresponding exterior angles is that the sum of the measures of the exterior angles is always equal to 180 degrees. This is known as the Exterior Angle Theorem.
Since
45 + 5x = 9x + 9 (Exterior Angle Theorem)
Collect like terms
45 - 9 = 9x - 5x
36 = 4x
x = 6
The exterior angle is;
9(6) + 9
= 63 degrees