Answer:
4
Explanation:
the third angle of the inner triangle is defined by using the rule that the sum of all angles in a triangle must be 180 degrees. let's call this angle a
180 = 48 + 16x + a
132 - 16x = a
and then we know that both angles, 28x and a together must also be 180, as they are complementing each other to cover the whole top of the base line.
so,
28x + 132 - 16x = 180
12x = 48
x = 4