title: "R\u00fcmwinkel"
text: "A R\u00fcmwinkel  of  as en miat uun't traad dimensioon. Hi beskraft di uundial fan di r\u00fcm, di en keegel uun en kuugel iinnamt.\n\nSodenang as diar en graten ferskeel tu en winkel uun en flaak.\n\nBeskriiwang \nDi r\u00fcmwinkel  as f\u00e4\u00e4stlaanj \u00fcs areal  faan en dial faan't kuugelflaak, diald troch det kwadroot faan di raadius faan det kuugel:\n\n \n\nBi't ianhaidskuugel () as  detsalew \u00fcs di r\u00fcmwinkel. Di fol r\u00fcmwinkel as diarm\u00e4 so grat \u00fcs det kuugelflaak: .\n\nDet areal s\u00e4\u00e4r n\u00e4\u00e4n kreis wees (so \u00fcs uun det tiaknang rochts). Wan't detsalew grate h\u00e4\u00e4, do h\u00e4\u00e4 det uk disalew r\u00fcmwinkel.\n\nIanhaid \nUk wan di r\u00fcmwinkel eegentelk nian dimensioon h\u00e4\u00e4, woort hi miast uun Steradiant (sr) meeden, auer det d\u00fc\u00fctelker as. \n\nEn r\u00fcmwinkel faan 1\u00a0sr h\u00e4\u00e4 \u00fc\u00fcb en kuugel m\u00e4 en raadius faan 1\u00a0m en areal faan 1\u00a0m2. Tu't hialer kuugel hiart oober en flaak faan , sodenang as di fol r\u00fcmwinkel:\n\n.\n\nLuke uk diar \n\nGeometrii"