In the triangle above, does a2 + b2 = c2 ?

(1) x + y = 90

(2) x = y

Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

EACH statement ALONE is sufficient.

Statements (1) and (2) TOGETHER are NOT sufficient.

##### 考题讲解

（1）    根据条件1，如果x+y=90，则该三角形为直角三角形，满足~$a^2+b^2=c^2$~。

（2）    根据条件2，满足x=y的三角形不一定为直角三角形，例如x=y=60，该三角形为等边三角形，不满足~$a^2+b^2=c^2$~。