góc xOy=góc x'Oy'
góc yOz'=góc zOy'
góc xOz'=góc x'Oz
góc xOz=góc x'Oz'
góc xOy'=góc x'Oy
Các cặp góc bằng nhau:
\(\widehat{xOy}=\widehat{x'Oy'}\)
\(\widehat{yOz'}=\widehat{zOy'}\)
\(\widehat{xOy'}=\widehat{x'Oy}\)
\(\widehat{xOz'}=\widehat{x'Oz}\)
\(\widehat{xOz}=\widehat{x'Oz'}\)
\(\widehat{yOz}=\widehat{y'Oz'}\)

