Answer: 20 units
Step-by-step explanation: The diagonal forms a Right Triangle with the side opposite the 30° angle, and the hypotenuse is the base. In a 30, 60, 90 triangle, the hypotenuse is always twice the length of the short side, given as 4. So the base is 8.
The upper triangle is iscosceles, and the trapezoid is iscosceles, so the other sides are all 4 units in length.
3×4=12
8+12=20 units