For all of these you can count the number of blocks over to find two sides of the triangle.
For example: the first one has two sides, one is 3 units, the other is 5. To find the missing angle you square 3 and 5, then add that together. That is equal to 34. 34 = c^2. To get the c by itself, you then take the square root of 34. So the missing side (c) is equal to 5.83.