Geomerty question

[TWCReborn]

Using the above 2 relationships, you would first show that blue is equal to green+pink and blue is equal to red plus yellow. Thus b = g+p = r+y. To show b = g+r, you must show p = r (can be seen by substitution).

The last part of the puzzle was pointed out above. You can equate red to pink since they subtend the same chord (the lines forming the angles touch the same 2 points on the circle, and thus the vertex, even if you move it around, as long as it is touching the circle will have the same angle).

Plugging in r=p to b=g+p, you get b=g+r.