有个正在上初三的女儿,做数学题时用到了勾股定理,知道直角三角形的两条直角边分别是9厘米和12厘米,求第三条边的长度。算了一会儿,她说,第三条边的长度怎么还带有根号啊?我一听,晕,都初三的学生了,居然不能一眼看出直角边为9和12的直角三角形的斜边应该是15,只知道一味地死套公式,结果还算错了。孩子对于边长分别是3、4、5的直角三角形非常熟悉,早就知道“勾三、股四、玄 There is a daughter on the third day, when used to do the math problems Pythagorean theorem, know right-angled triangle of two right-angled sides were 9 cm and 12 cm, find the length of the third side. For a moment, she said, the length of the third side how rooted ah? I heard, halo, all three students, actually can not see the right-angle side of the right-angled triangle 9 and 12 of the oblique The edge should be 15, only know blindly die formula, the result is still wrong. Children are very familiar with the side length of 3,4,5 right-angled triangle, have long been aware of ”hook three, four stocks, mysterious