问题
填空题
△ABC中，AB=AC=12，AC的垂直平分线交AB于D，交AC于E，当BC=4时，△DBC周长是______．
答案
∵DE是AC的垂直平分线，
∴AD=CD，
∵AB=AC=12，BC=4，
∴△DBC周长是：BC+CD+BD=BC+AD+BD=BC+AB=4+12=16．
故答案为：16．
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△ABC中，AB=AC=12，AC的垂直平分线交AB于D，交AC于E，当BC=4时，△DBC周长是______．
∵DE是AC的垂直平分线，
∴AD=CD，
∵AB=AC=12，BC=4，
∴△DBC周长是：BC+CD+BD=BC+AD+BD=BC+AB=4+12=16．
故答案为：16．
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| Nowadays we call see more and more electric bikes in the street. Electric bikes are easy to 1 and they can run faster than ordinary bikes. So they become very 2 in many cities in China now. But the electric bikes also 3 many traffic accidents happen. So the Chinese government plans to make a new 4 for the electric bike riders (骑车者). If 5 electric bike is heavier than 40 kilos and it can go 6 than 20 kilometers an hour, its rider must get a license (执照). It means riders have to pass driving test 7 they ride their electric bikes on the road. People have different ideas about the rule. Some people like the rule 8 they think it will make the street much safer. But some people are not 9 the new rule at all. One rider said, "I don't want to get a license or 10 , I don't like too many rules in life." What's your idea, my friends? | ||||
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