Question

指針從“12”繞點(diǎn)O順時(shí)針旋轉(zhuǎn)90°到“

3

”． 
指針從“6”繞點(diǎn)O順時(shí)針旋轉(zhuǎn)90°到“

9

”．
指針從“9”繞點(diǎn)O逆時(shí)針旋轉(zhuǎn)

90°

到“6”．
指針從“3”繞點(diǎn)O逆時(shí)針旋轉(zhuǎn)180°到“

9

”．

Answer 1

分析：鐘面上12個(gè)數(shù)字把鐘面平均分成12份，每份所對(duì)應(yīng)的圓周角是360°÷12=30°，即每?jī)蓚�(gè)相鄰數(shù)字間的夾角是30°，即指針從一個(gè)數(shù)字走到下一個(gè)數(shù)字時(shí)，繞中心軸旋轉(zhuǎn)了30°，據(jù)此解答．

解答：解：指針從“12”繞點(diǎn)O順時(shí)針旋轉(zhuǎn)90°到“3”． 
指針從“6”繞點(diǎn)O順時(shí)針旋轉(zhuǎn)90°到“9”．
指針從“9”繞點(diǎn)O逆時(shí)針旋轉(zhuǎn)90°到“6”．
指針從“3”繞點(diǎn)O逆時(shí)針旋轉(zhuǎn)180°到“9”．
故答案為：3，9，90°，9．

點(diǎn)評(píng)：解答此題的關(guān)鍵是弄清指針旋轉(zhuǎn)一個(gè)數(shù)字所旋轉(zhuǎn)的度數(shù)．