So 3/6 of the numbers on a cube are even. It will be rolled twice so you multiply 3/6 by 3/6 and get 9/36. This means 9 of the 36 possible outcomes will have 2 even numbers. It could be 2 and 2, 2 and 4, 2 and 6, and so on.
The exterior angles of a triangle always add up to 360 degrees. Using this, you can set up the following equation.
3y+4y+5y=360
y=30 degrees
The smallest interior angle corresponds to the largest exterior angle. 5y=5*30= 150. Subtracting this from 180 you get 30 degrees, or the smallest interior angle. Hope this helps!