Bir khaas ah 20 # hexagon 45 # hexagon 16Mn bir laba jibaaran

Birta qaabka gaarka ah u qaabaysan waa mid ka mid ah afarta nooc ee birta ah (nooc, xariiq, saxan, tuubo), waa nooc ka mid ah birta si weyn loo isticmaalo. Marka loo eego qaabka qaybta, birta qaybta waxaa loo qaybin karaa qaybta fudud ee birta iyo qaybta adag ama qaabka gaarka ah (birta gaarka ah). Dabeecadda hore waa in aysan ka gudbeynin qaybta isdhaafka ah ee dhibic kasta oo ku taal hareeraha xariiqda tangent. Sida: bir laba jibaaran, bir wareegsan, bir fidsan, bir xagal ah, birta laba geesoodka ah, iwm; Biraha caadiga ah ee qaabka gaarka ah waxaa ka mid ah birta daaqada kulul, wadaaga birta, birta qaybta kulul ee gawaarida gawaarida gawaarida, qaybta kulul ee birta ee saxanka wadada, birta qaybta kulul ee gawaarida gawaarida, tareenka, birta guri ee dhismaha maraakiibta, birta fiilada, birta xoqan iyo wixii la mid ah.