The formula you need to know is that the side opposite of the 30° angle is always half the hypotheneus. For example in question 2 X should be 6 since 3 is opposite side of the angle 30°. In a 45 45 90 triangle, it is important to know that the straight sides are always the same length (since they are the same angle). For example in question 9, v is also 9√2.
When you have two sides, you can figure out the third side with a² + b² = c² since they are all right triangles. Good luck
