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歡迎您訪問數學考題練習:鐘表上2時25分時,時針與分針所成的角是!

數學考題練習:鐘表上2時25分時,時針與分針所成的角是

更新時間:2024-01-12 16:29:48作者:貝語網校

鐘表上2時25分時,時針與分針所成的角是

A.77.5°

B.77°5′

C.75°

D.以上答案都不對

試題答案

A

試題解析

畫出圖形,利用鐘表表盤的特征解答.

解答:解:我們把時針指向2,分針指向12作為起始位置,

當分針指向25時,他轉了25×6°=150°,

此時時針轉動了150°×=12.5°,

則時針和3之間還有30°-12.5°=17.5°,

故時針和分針之間夾角為30°×2+17.5°=77.5°.

故選A.

點評:本題考查鐘表時針與分針的夾角.在鐘表問題中,常利用時針與分針轉動的度數關系:分針每轉動1°時針轉動()°;兩個相鄰數字間的夾角為30°,每個小格夾角為6°,并且利用起點時間時針和分針的位置關系建立角的圖形.

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