请大家帮助解答GWD15 的26题

猫猫咪伢

Q26:
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In the figure shown, the circle has center O and radius 50, and point P has coordinates (50,0).If point Q (not shown) is on the circle, what is the length of line segment PQ ?
(1)The x-coordinate of point Q is – 30.
(2)The y-coordinate of point Q is – 40.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
Answer:
为什么答案是A？如果（1）可以为什么（2）不能？

囧豌豆

（1）Q的横坐标确定，且Q在圆上，所以Q的坐标为（-30，40）或（-30，-40），p到这两点的距离是一样的。。
（2）Q的纵坐标确定，且Q在圆上，所以Q的坐标为（-30，-40）或（30，-40），P到这两点的举例明显不一样，所以不能确定PQ的长度。。

lz 画个图仔细看看。。

猫猫咪伢

明白了，非常谢谢！

昵昵大人

唉，题上又没说O就是原点0。。。。。被误导了。。。。。。