So all of the angles in a triangle add up to 180 degrees and so if you split the triangle into separate triangles then you can add up the angles that are known and subtract from 180 to get the size of the missing angle e.g 90 + 56 = 146, 180 -146 = 34 for the other triangle 90 + 26 = 116, 180 - 116 = 64 and so 64 - 34 = 30
This equation would be the associative property because you would have the ability to add or multiply these numbers, regardless of how they were grouped together
