【求助】数学PREP07 DS1 第181题

xiaoxuanchu

这是一道图形题（不知道怎么把图贴上来）
In the figure shown, what is the value of x ?


(1)The length of line segment QR is equal to the length of line segment RS.


(2)The length of line segment ST is equal to the length of line segment TU.

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【答案】C

【思路】

(1) QR=RS 不能判斷x

(2) ST=TU 不能判斷x

(1)+(2)
RSQ=RQS && TSU=SUT

SUP=x+
TSU（这是怎么推导出来的啊？）


SQP=x+
RSQ   

SUP+SQP=180+x

QPU+180+2x = 360 (四邊形內角和)
2x=90, x=45