考题9-10 2014 AMC 8

AMC 8数学竞赛专为8年级及以下的初中学生设计，但近年来的数据显示，越来越多小学4-6年级的考生加入到AMC 8级别的考试行列中，而当这些学生能在成绩中取得“A”类标签，则是对孩子数学天赋的优势证明，不管是对美高申请还是今后在数学领域的发展都极其有利！那么接下来跟随小编来看一下AMC 8数学竞赛试题及答案吧：

Problem 9

In ,  is a point on side  such that  and  measures . What is the degree measure of ?

Solution

BD = DC, so angle DBC = angle DCB = 70. Then CDB = 40. Since angle ADB and BDC are supplementary, .

Problem 10

The first AMC  was given in  and it has been given annually since that time. Samantha turned  years old the year that she took the seventh AMC . In what year was Samantha born?

Solution

The seventh AMC 8 would have been given in 1991. If Samantha was 12 then, that means she was born 12 years ago, so she was born in 

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