[Visitor (112.21.*.*)]answers [Chinese ]  Time :20210210  Fill corners
If the two corners of the total meet the 180 degrees plus 2k (k∈Z), then the two corners complement each other. One corner is called the complement angle of the other.
Note: The position of the two corners does not affect their complementary angles, to determine whether the two corners complement each other, only need to meet: the two corners of the and equal to 180 degrees plus 360 degrees k, k∈Z. 
