Complementary angle add up to 90 degrees
UOI and UIO Triangles add to 180 and the IUO is 90 degrees so that leaves 90 degrees to the other 2 angles
AOU AND UOA Triangles add to 180 and the AUO is 90 degrees so that leaves 90 degrees to the other 2 angles
AIE AND EIA Triangles add to 180 and the IEA is 90 degrees so that leaves 90 degrees to the other 2 angles
supplementary angle add up to 180 degrees
Complementary pairs: UOI and UIO , AOU AND UOA ,AIE AND EIA
AUO and IUO Straight lines add to 180
AEI AND OIE 2 corners of the figure
EAO AND AOI 4 sided figures add to 360 and the other 2 corners are 90 each which is 180 so that leaves 180 for these 2 angles
Supplementary pairs: AUO and IUO ,AEI AND OIE, EAO AND AOI