TETRAEDR

TETRAEDR (yunoni tetraedron, az yunoni Tetrarop va hedra — asos, ruya), yake az 5 namudi bisyorruyai muntazamro guyand (rasm), ki 4 ruya (sekunjavi), 6 tega, 4 qulla (dar har yak qulla 3 tega ba ham merasand) dorad. Agar a — darozii tegai Tetraedr boshad hajmi on az rui formulai V = ~ 0,1179 v3 hisob meshavad. Tetraedr piramidai muntazam ast.