Question

8．指針從“1”繞點O順時針旋轉(zhuǎn)60°后指向3；   指針從“1”繞點O逆時針旋轉(zhuǎn)60°后指向“10”；指針從（“2”）繞點O順時針旋轉(zhuǎn)180°后指向“8”．

Answer 1

分析 鐘面上12個數(shù)字把鐘面平均分成12份，每份所對應(yīng)的圓心角是360°÷12=30°，即每兩個相鄰數(shù)字間的夾角是30°．指針從“1”繞點O順時針旋轉(zhuǎn)60°后指向3；   指針從“1”繞點O逆時針旋轉(zhuǎn)60°后指向“10”；指針從（“2”）繞點O順時針旋轉(zhuǎn)180°后指向“8”．

解答 解：指針從“1”繞點O順時針旋轉(zhuǎn)60°后指向3；   指針從“1”繞點O逆時針旋轉(zhuǎn)60°后指向“10”；指針從（“2”）繞點O順時針旋轉(zhuǎn)180°后指向“8”．
故答案為：3，60，2．

點評 解答此題的關(guān)鍵是弄清鐘面上相鄰兩個數(shù)字間的夾角是30°．可找一鐘表模型操作一下．